tag:blogger.com,1999:blog-20643496648514627322024-02-18T20:37:33.318-08:00The Pheidole megacephala CompendiumPMC highlights studies, notes, and my own personal accounts of one of the world's most aggressive and invasive ant species, Pheidole megacephala, which is commonly known as the Big Headed Ant (BHA) or Coastal Brown Ant.BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-2064349664851462732.post-9185017540492656212020-03-04T08:08:00.001-08:002020-03-04T16:03:55.723-08:00On the longevity of Pheidole megacephala Colony Clusters<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEVAq1QXzVKUW2R02N4JWm9RqNjIUg31c742P4ZMYws_PyHnmpc-ONEUV_VGFyodG6UwFgtWuO2kgJgy8Jd9-HICmzu1L098jD0MegP1CY7frJDplLDuLZ1z6SGG4A-A11v4_rfBbl5WY/s1600/map.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="530" data-original-width="644" height="328" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEVAq1QXzVKUW2R02N4JWm9RqNjIUg31c742P4ZMYws_PyHnmpc-ONEUV_VGFyodG6UwFgtWuO2kgJgy8Jd9-HICmzu1L098jD0MegP1CY7frJDplLDuLZ1z6SGG4A-A11v4_rfBbl5WY/s400/map.png" width="400" /></a></div>
<b><br /></b>
<b>Citation: </b><br />
<i><br /></i>
<i>Sunjian, A (2020). On the longevity of Pheidole megacephala Colony
Clusters. The Pm Compendium (PMC).
https://pheidolemegacephala.blogspot.com/2020/03/on-longevity-of-pheidole-megacephala.html</i><br />
<br />
<b>Abstract</b><br />
<br />
More than 30 years after being discovered in the Marie Selby Botanical Gardens in Sarasota, FL,<br />
<i>Pheidole megacephala</i> is still present in force along the more open southwestern end, while eschewing the tree-covered areas of the park. This confirms the longevity of <i>P. megacephala</i> colony clusters. In addition, the species occupies approximately 25 hectares of the western bay area north of the gardens, where it excludes most other ants. It is also extremely likely that the boundaries of the cluster extend much farther north along the bay front, beyond the surveyed area,<br />
<br />
<b>PDF of Full Article:</b><br />
<br />
<a href="https://drive.google.com/file/d/1EV5ChnBuA1uDXlbre5QzYEcpDZnUU_M3/view?usp=sharing" target="_blank">On the longevity of Pheidole megacephala Colony Clusters</a><br />
<br />
<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-74054493006765101782019-04-26T19:17:00.002-07:002019-04-26T19:21:24.842-07:00Excerpt: Interactions between Pheidole megacephala and Linepithema humile in Oahu, Hawaii by Sam S. Fluker<b><i>Excerpt from the paper by Sam S. Fluker, "Sympatric associations among selected ant species and some effects of ants on sugarcane mealybugs in Hawaii" (1969)
</i></b><br />
<br />
In tests conducted in the laboratory, it was found that when colonies of Argentine ants (<i>Linepithema humile</i>) or <i>Pheidole megacephala </i>were placed in contact with a colony of <i>Anoplolepis gracilipes</i>, the workers
and queens of A. gracilipes were always destroyed and the brood was taken as food by the other ant. A. gracilipes seemed to make no effort to defend itself or the brood. Instead the workers would run about the enciosure in panic and most would be killed by running into the "Tanglefoot" barrier rather than in fights with the other ants.
<br />
<br />
Colonies of Argentine ants and Pheidole which had been maintained in the laboratory for three weeks were put together so that there was continuous contact along one side of the nest platforms. Within ten minutes, the
whole colony of Argentine ants had crossed over to the
Pheidole platform. This invasion included not only
workers but the brood and many queens as well.
There seemed to be no concentrated attack by the
Argentine ants; however, there were chance encounters
caused by the Argentine ants scurrying about. An occasional
Argentine ant would go into the area where the
Pheidole colony was concentrated. It would be immediately
attacked by one or more Pheidole workers and usually would be killed.
The only unusual excitement in the Pheidole nest was caused by the
occasional invasion by an
Argentine ant. However, there seemed to be a response to
the invasion throughout the Pheidole colony whereby the
Pheidole began to seal the entrances to the nest with
trash as a protective measure.
<br />
<br />
In less than 90 minutes, the Argentine ants had moved
all their brood and queens back into their original colonies
with only an occasional Argentine ant venturing onto
the Pheidole platform. when an Argentine ant would cross over
to the other platform, it would only go to the outer perimeter.
<br />
<br />
After four hours, there was no sign that either ant
would attack the other in sufficient numbers to eliminate
the colony. The Argentine ants still moved about their
platform in the usual foraging manner, occasionally crossing over
to the Pheidole piatform. The Pheidoe were
still in the process of sealing the entrances to their
nest. There were a few soldiers ani workers of PheidoZe
on the Argentine platform.
<br />
<br />
At five hours after beginning the experiment, the
Argentine ants began moving their brood from one nest to
another. In a short time the colony became very excited
and started moving the brood out of both nests and eventually
setitied down at the opposite end of the platform
from the nests. This excitation of the colony seemed to
have been preceded by the invasion of the Argentine ant
colony by four or five Phetdote soldiers, The Argentine
ants seemed to go out of their way to avoid contact with
the soldiers, : even when the soldiers were injured.
Pheidole soldiers are much slower in their movements than
the Argentine ant workerss; but they snap their mandibles
at any moving object whichi near They will do this to
even their own species when they are very excited.
<br />
<br />
After a 12 hour period had elapsed, the Argentine ant
colony was still grouped with their queens and brood at
the corner of the platform farthest from the nests. After
the lights in the laboratory had been on for five to
ten minutes, the Argentine ants began to move back into
the two nests. Within a period of ten minutes, they
had moved al1 of their brood back into the nests.
At this time there was very little disturbance of the
Argentine ant colony by Pheidole.
<br />
<br />
At 24 hours from the beginning of the experiment,
the complete Argentine ant colony had moved again. This
time they moved from the nests into the corner farthest from the Pheidole and their own nests. At this point
in time, the former Argentine ant nests were occupied by
six to ten Pheidole soldiers and approximately fifteen
workers in each nest. The Argentine ants appeared to be
very sluggish in their movements and were making no attempt to
re-establish themselves in their nests. Even when a
75-watt 1ight was turned on directly above them, no attempt
was made to protect themselves or their brood from the light. The colony of Pheidole seemed to be engaged in
its normal activities without undue excitement,
<br />
<br />
Late in the morning of this second day of observations, another
artificial nest was put on the platform
containing Argentine ants. The colony immediately began
moving into the nest. In less than 20 minutes the entire
colony of Argentine ants was inside the nest.
<br />
<br />
Approximately four hours later, the colony of Argentine
ants was still in the new nest with the Pheidole occupying
the original Argentine ant nests.
<br />
<br />
At eight o clock in the morning of the following day,
it was observed that the Argentine ants had moved out of
the new artificial nest and were on top and to one corner
of the nest. Shining bright lights on the colony did not
force them to move. Only one Pheidole was seen in the
nest which the Argentine ants had vacated.
<br />
<br />
The experiment explained above was repeated in the
laboratory four times. Each experiment ended with
Pheidole having possession of the nests and the Argentine
ants huddled in a corner as far away from Pheidole as they
could possibly get.
<br />
<br />
A later experiment consisted of placing a small colony of
Argentine ants in an artificial nest with sand
completely covering the floor of the platform to a depth
of one-half inch. This platform was connected to another
platform containing a very large colony of Pheidole. The
Argentine ants immediately began to cross over to the
Pheidole platform. There were so many Pheidole at the
base of the bridge that the Argentine ants were unsuccessful
in crossing over to the other platform. When one
would try to make the crossing, it would be immediately
attacked by Pheidole soldiers and workers. This situation was
observed for one hour. The following morning, it was
noted that the complete colony of Argentine ants had been
killed by the Pheidole ants. The nest which had been
originally occupied by the Argentine ants was inhabited
by Pheidole. Upon close examination, it was observed
that numerous Pheidole workers were carrying brood to
their original nests. It was determined that this was
the Argentine ant eggs, larvae and pupae which were
probably used as food by the Pheidole colony.
<br />
<br />
In efforts to establish Argentine ants in the ant infested
plots of sugarcane at the Waimanalo Experiment
Station, two large colonies of Argentine ants were brought
from Wailua Agriculture Company Field Opaeula Number Nine
to the Waimanalo plots. The ants were transported from Wailua
to Waimanalo in heavy plastic bags The two plastic bags
containing the ants were placed at the edge of
the plot and a hole was punched in each bag. This hole
was made to allow the insertion of a sugarcane leaf into
the bags. The leaf was positioned so that the ants would
move along the leaf to a horizontal cane stalk which was
lying on the ground. Some loose soil had been previously
placed over a portion of the stalk about three feet from
the plastic bags as a possible nest. The ants immediately
began moving their brood from the plastic bags to the place
where the soil was covering the stalk. By close
observation, it was noted that the workers would take
the brood to the soil covering the stalk and return to
the plastic bags for more brood.
<br />
<br />
During six hours of almost constant observation,
there was a steady stream of workers with brood going to
the new nest from the plastic bags and returning empty
to the bags after more brood. At the end of six hours,
it was noticed that some Pheidole soldiers and workers
were at the base of the sugarcane stalk approximately
two feet from the nest. At the same time large numbers
of Pheidole soldiers and workers were observed on the
ground about one foot from the Argentine nest. Within
four hours after the first Pheidole was seen in the vicinity
of the Argentine ant nest, the Pheidote ants had moved into
the Argentine ant nest with the result that the
Argentine ants had moved their brood out of the nest and
through an area which had been treated with 2.58 Dieldrin
granules. The Argentine ants moved even though they outnumbered
the Pheidole tremendously. There were close to ten
thousand Argentine workers in the nest and less than one
hundred Pheidole near the area.
<br />
<br />
Argentine ants were introduced to the Waimanalo
Experiment Station plots on several occasions prior to
this using similar methods. Each time they disappeared,
so this particular attenpt was made to determine their
actions and movements.
<br />
<br />
The behavior exhibited by Pheidole and the Argentine
ants suggests that glandular secretions are involved and
play a large role in the behavior on one ant toward the
other. Crowell (1968) theorized that the Argentine ant
released some type of glandular secretion which was very
repugnant to Pheidole, causing Pheidole to move away from concentrations of Argentine ants. If indeed there is a
chemical repellent released by the Argentine ants, my
studies seem to indicate that only under certain conditions
do the Argentine ants release this glandular secretion.
This appears to be during the time immediately
preceding an invasion of new territory by the Argentine
ants. If a glandular secretion is produced by the
Argentine ants, this could account for the "Buffer Zone"
that is commonly found separating the Argentine ants and
Pheidole during the former's "invasion cycle". At other
times, Argentine ant and Pheidole colonies are found very
close together.
<br />
<br />
The studies conducted in the laboratory and sugarcane
plots at Waimanalo Experiment Station appear to indicate
that the Pheidole soldier may release a glandular secretion
that is offensive to the Argentine ants. The action
of the Argentine ant in the presence of the Pheidole soldier
suggests this possibility. Although the Argentine
ants will attack and kill Pheidole workers and will continue
to mutilate their bodies after death, the Argentine
ants appears to go to great extremes to avoid a Pheidole
soldier. Even if the Argentine ants far outnumber the
Pheidole soldiers, they will make no attempt to attack.
No attempt was made to determine if the Pheidole soldier
has a glandular secretion that was responsible for the
actions of the Argentine ants. However, I find it difficult
to believe that the mere physical presence of a few
Pheidole soldiers is all that is needed to cause a colony
of thousands of Argentine ants to abandon otherwise suitable nesting sites.
BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-46900554558627730762019-03-14T05:19:00.000-07:002019-03-14T11:13:56.311-07:00Step aside, fire ants, there’s a new, big-headed, six-legged female sheriff in town<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmzIk8Cb3K2HiZjingfhl-Qzs67vZH6WS0-UyOFjkciWd6P4VZITMysHjmbFw18uADLL46UHIt3AYV4hmcjTnUTh6cXi8fFVT26QJThIbw6Smhrpn64WhaO4E373O3SdogL41em9vvDT0/s1600/bigheaded_ant13.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="349" data-original-width="500" height="278" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmzIk8Cb3K2HiZjingfhl-Qzs67vZH6WS0-UyOFjkciWd6P4VZITMysHjmbFw18uADLL46UHIt3AYV4hmcjTnUTh6cXi8fFVT26QJThIbw6Smhrpn64WhaO4E373O3SdogL41em9vvDT0/s400/bigheaded_ant13.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Photograph by R.H. Scheffrahn, University of Florida</td></tr>
</tbody></table>
<br />
I woke up and read two interesting news articles.<br />
<br />
The articles noted that "bigheaded ants", which presumably are <i>Pheidole megacephala</i>, <a href="https://www.nbc-2.com/story/40122474/bigheaded-ants-are-invading-south-florida" target="_blank">have slowly been taking over south florida</a> and pushing aside the usual fire ants (<i>Solenopsis invicta</i>).<br />
<br />
In a way, this is not very surprising. The status of <i>P. megacephala</i> as a pest ant in or<br />
near structures in that region rose from the 7th spot in 1995 (Klotz et al, 1995) to the top<br />
spot by 2007 (Warner and Scheffrahn, 2007).<br />
<br />
It was also interesting that when I traveled to the state in 2018 <a href="https://pheidolemegacephala.blogspot.com/2018/06/a-survey-of-ants-in-old-town-key-west.html" target="_blank">to survey Key West</a>, both of the two hotels I stayed in (one in Marathon in the Florida Keys, the other in Homestead, which is south of Miami) had <i>P. megacephala</i> colony clusters in them. I had found that a very remarkable coincidence at the time, but perhaps I should not have been that surprised. When I traveled to Fort Lauderdale earlier this month I also easily found the species in an urban park (I was only in the city for one day), where it and <i>S. invicta</i> have co-existed since at least the 1980s.<br />
<br />
The cause of this upsurge in the species is not known, although Warner and Scheffrahn in 2007 stated it might have been because of new plantings of trees to replace those damaged due to hurricanes in that area.<br />
<br />
Another possibility that comes to mind is that the climate in that state may be slowly changing to better accommodate the species, which is normally constrained by abiotic factors. <i>P. megacephala</i> prefers moisture and warmth, and is easily desiccated.<br />
<br />
As an aside, it's kinda annoying that the ant they show in one video is not the right species, but I guess they had to show a larger ant for the cameras (even the majors in <i>P. megacephala</i> are small at 4 mm or less). Fortunately, the other article's video had the right species *smh*.<br />
<br />
The two articles:<br />
<br />
<a href="https://www.news-press.com/story/tech/science/environment/2019/03/07/bigheaded-ants-invade-homes-property-creating-giant-hard-kill-colonies/2994767002/" target="_blank">Step aside, fire ants, there’s a new, big-headed, six-legged female sheriff in town</a><br />
<br />
<a href="https://www.nbc-2.com/story/40122474/bigheaded-ants-are-invading-south-florida" target="_blank">'Bigheaded' ants are invading South Florida</a><br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-55299534977821790912019-03-10T09:01:00.001-07:002019-04-27T08:13:29.159-07:00Pheidole megacephala in George Town, Grand CaymanCitation: <i>Sunjian, A (2019). Pheidole megacephala in Georgetown, Grand Cayman . The Pm Compendium (PMC). https://pheidolemegacephala.blogspot.com/2019/03/pheidole-megacephala-in-georgetown.html</i><br />
<br />
Abstract<br />
<br />
A visual survey of the downtown area of Georgetown, Grand Cayman in March 2019 revealed the presence of <i>Pheidole megacephala</i>, which had been absent in previous surveys. A mapping of the current range of the colony cluster in the city showed that it occupied at least one block, an area of approximately 1 hectare. No other ant species were found in that area, although <i>Paratrechina longicornis</i>, a <i>Brachymyrmex</i> sp., <i>Trichomyrmex destructor</i>, and <i>Solenopsis invicta</i> fire ants were present surrounding that block.<br />
<br />
PDF of Full Article:<br />
<br />
<a href="https://drive.google.com/file/d/1ua6sOfQtWxSOVR4s7zbmWxSiW2_Z74T_/view?usp=sharing" target="_blank">Pheidole megacephala in Georgetown, Grand Cayman</a>BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-19880549018222244462018-06-27T09:28:00.000-07:002019-04-27T08:12:53.991-07:00A survey of ants in Old Town Key West in Florida and a review of Pheidole megacephala as an archetypal “hegemonic” species<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEIzvdp2NpkDg8g7fxE7_uaBN9oFUxOw9QkAdpIyoYHQqf_GSnrM3tLml3OtO1WqVevNLwJQURWFZgYK03wnFBUiuvH3F9HE9te3ShzwvID72fTjawPYxAsUkd9UBPVN4huZ2uTYnm_3g/s1600/keywest.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="511" data-original-width="771" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEIzvdp2NpkDg8g7fxE7_uaBN9oFUxOw9QkAdpIyoYHQqf_GSnrM3tLml3OtO1WqVevNLwJQURWFZgYK03wnFBUiuvH3F9HE9te3ShzwvID72fTjawPYxAsUkd9UBPVN4huZ2uTYnm_3g/s400/keywest.png" width="400" /></a></div>
<div style="margin-bottom: 0in;">
<span style="font-size: medium;"><br /></span></div>
<div style="margin-bottom: 0in;">
Citation: <i style="font-family: "Times New Roman", serif;">Sunjian,
A (2018). A survey of ants in Old
Town Key West in Florida and a review of Pheidole megacephala as an
archetypal “hegemonic” species. The Pm Compendium (PMC).
https://pheidolemegacephala.blogspot.com/2018/06/a-survey-of-ants-in-old-town-key-west.html</i><br />
<br />
Abstract:</div>
<div style="margin-bottom: 0in;">
<span style="font-size: small;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
A
two-day visual survey of Old Town Key West in Florida in May 2018 was
conducted to determine the distribution of urban ants in this city.
The census covered approximately 230 hectares and revealed that the
area was partitioned into mutually exclusive territories by a
<i>Pheidole megacephala</i> cluster on the northern end, and fire ant
colonies (<i>Solenopsis invicta</i> and <i>S. geminata</i>) towards
the south, although various other non-dominant species were also
present. Only a single specimen of the formerly dominant <i>Trichomyrmex
destructor</i> was collected during the survey, and its replacement
in the city center is discussed within the context of a detailed
review of the role of <i>P. megacephala</i> as a so-called “hegemonic
species”.</div>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
PDF of Full Article:</div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-size: medium;"><br /></span></div>
<div style="margin-bottom: 0in;">
<a href="https://drive.google.com/file/d/1qZ1xvz5uw3mUc6fqU-bsfCc9kW7h4JTT/view?usp=sharing" target="_blank">A survey of ants in Old Town Key West in Florida and a review of <i>Pheidole megacephala</i> as an archetypal “hegemonic” species</a></div>
<div style="margin-bottom: 0in;">
<span style="font-size: medium;"><br /></span></div>
<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-66069434993522598922018-03-19T11:28:00.004-07:002019-04-27T08:14:44.074-07:00Pheidole megacephala in Harare, Zimbabwe<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHc585JH2hLctf7tV_detFw1tnlA5ppNsxaLy0_7Oz6SFRjPf_xsF3B9zohIt5l-dkfIn6-xEWPrwMsRtYTGQRCINtSo3CplXDUkE8-mFBozgyGSueegWoBPbeP_MV3xLykarUCvHqM6M/s1600/Harare_Skyline.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="266" data-original-width="604" height="175" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHc585JH2hLctf7tV_detFw1tnlA5ppNsxaLy0_7Oz6SFRjPf_xsF3B9zohIt5l-dkfIn6-xEWPrwMsRtYTGQRCINtSo3CplXDUkE8-mFBozgyGSueegWoBPbeP_MV3xLykarUCvHqM6M/s400/Harare_Skyline.jpg" width="400" /></a></div>
<br />
<i>Note Citation: Wetterer, JK (2018). Pheidole megacephala in Harare, Zimbabwe . The Pm </i><i>Compendium </i><i>(PMC). https://pheidolemegacephala.blogspot.com/2018/03/new-records-of-pheidole-megacephala-in.html</i><br />
<br />
Dr. James Wetterer, whose research focuses on the distribution and ecology of invasive ant species, surveyed Harare in Zimbabwe, as well as the town of Kariba, and some points in between in 2012.<br />
<br />
He noted that "at all sites in Harare and a nearby game reserve, <i>Pheidole megacephala</i> dominates and few other species are to be found. I don't even find other widespread tramps."<br />
<br />
Click <a href="https://drive.google.com/open?id=1lUC5g0c0n1s3HjMpsMMYd4fQY-Ui_Lx6&usp=sharing" target="_blank">here for google map</a> of <i>P. megacephala</i> samples.BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-6723446923037442262018-02-20T13:48:00.002-08:002018-03-19T08:04:29.950-07:00What are colony clusters?<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9gZ0xQJU-3iwO9N0N4l7-DX5iyQB3gG42zUkBuQBbI-7a2fTJnLPEBfKsfuE17Z8f80S87DsCv0ON24SBbMBq5pMG42byH_htAeRzefr4OSSbk-IgGzwu3OSVEQEFNkegu2IU3RkJMNc/s1600/pm.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="485" data-original-width="652" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9gZ0xQJU-3iwO9N0N4l7-DX5iyQB3gG42zUkBuQBbI-7a2fTJnLPEBfKsfuE17Z8f80S87DsCv0ON24SBbMBq5pMG42byH_htAeRzefr4OSSbk-IgGzwu3OSVEQEFNkegu2IU3RkJMNc/s400/pm.png" width="400" /></a></div>
<span id="goog_913283026"></span><span id="goog_913283027"></span><br />
I noticed I used the term "colony cluster" in the <a href="https://pheidolemegacephala.blogspot.com/2018/02/a-comprehensive-survey-and-mapping-of.html">latest survey</a>, so I wanted to define what the term means.<br />
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Although <i>P. megacephala</i> forms supercolonies, some of which may extend for thousands of kilometers, it is unlikely that they form a spatially contiguous and continuous population over entire land masses.<br />
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In this case, I wanted to use the term "colony cluster" to refer to a discrete population of a unicolonial species that is spatially separated more or less from other clusters within the supercolony. The separation may have come about because of natural or human-mediated dispersal of a propagule, or it may have been created by the partitioning of a larger community into separate communities due to encroachment by other species or other natural events.<br />
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Based on some studies, such colony clusters can remain active and viable for decades, something which is not possible for monogyne species.<br />
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A <a href="https://pheidolemegacephala.blogspot.com/p/colony-cluster-maps.html">new page in the website</a> is now dedicated to listing maps of <i>P. megacephala</i> clusters and the surrounding ant communities, which will hopefully be of help to researchers studying ant distribution and ecology.<br />
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<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-74693927580892805072018-02-08T09:36:00.001-08:002019-04-27T08:13:52.324-07:00A comprehensive survey and mapping of the Pheidole megacephala colony cluster in Bridgetown, Barbados<i>Citation: Sunjian, A (2018). A comprehensive survey and mapping of the Pheidole megacephala colony cluster in Bridgetown, Barbados . The Pm </i><i>Compendium</i><i> (PMC). https://pheidolemegacephala.blogspot.com/2018/02/a-comprehensive-survey-and-mapping-of.html</i><br />
<br />
ABSTRACT<br />
<br />
A visual survey of the downtown area of Bridgetown Barbados in January 2018 revealed the presence of Pheidole megacephala. It was the most collected species during the study, and was the only dominant ant present in the location. A mapping of the current range of this colony “cluster” showed that it extended at least from the Pelican Village Craft Center on the west to Independence Square on the east, with the northernmost limit near the James Street Methodist Church, a combined area of approximately 21 hectares. The possible introduction of this species into Barbados via a major renovation to the city port facilities in 2002 is discussed.<br />
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Click below for complete article in PDF format (revision date 2018-02-19):<br />
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<a href="https://drive.google.com/open?id=1ldVKoD5qh9p8aCeGz-C6Fukoly5E3A-x">A comprehensive survey and mapping of the Pheidole megacephala Colony Cluster in Bridgetown, Barbados</a></div>
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<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-6787398937968756502017-06-05T12:50:00.000-07:002019-04-27T08:14:11.599-07:00A Survey of the Distribution of Pheidole megacephala and Linepithema humile in Ireland Island North in Bermuda<br />
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<i>Citation: Sunjian, A (2017). A Survey of the Distribution of Pheidole megacephala and Linepithema humile in Ireland Island North in Bermuda. The Pm </i><i>Compendium</i><i> (PMC). https://pheidolemegacephala.blogspot.com/2017/06/a-survey-of-distribution-of-pheidole.html</i><br />
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Abstract<br />
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A survey of the locations of various ant populations in North Ireland Island in Bermuda revealed that the invasive <i>Pheidole megacephala</i> has continued to expand its territory at the expense of the equally invasive <i>Linepithema humile</i>, and has now become the dominant ant in this highly-disturbed area. However, pockets of the latter ant continue to exist, including a narrow corridor of territory cutting partly across the Royal Naval Dockyard from west to east.<br />
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<br />
Click for PDF:<br />
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<a href="https://drive.google.com/file/d/0B4qokt19LhvdX0lNd0hFeGg0Zmc/view?usp=sharing">A Survey of the Distribution of Pheidole megacephala and Linepithema humile in North Ireland Island in Bermuda (pdf)</a><br />
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<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-40314204108792714442017-02-20T10:55:00.001-08:002017-02-20T17:34:10.795-08:00New records of P. megacephala in St. John's, US Virgin Islands<i>Pheidole megacephala</i> has been reported from the US Virgin islands since the late 1800s. It shares the island group with various other exotic and invasive species, such as <i>Solenopsis geminata</i>, <i>Solenopsis invicta</i>, <i>Wasmannia auropunctata</i>, and <i>Paratrechina longicornis</i>.<br />
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In St. John's, Previous records of the species include:<br />
<br />
Location: 18.324,-64.788<br />
Location description: Great Cruz Bay, Hotel grounds<br />
Collection date: 2005-11-13<br />
Collector: Wetterer, J.<br />
<br />
Location: 18.331, -64.795<br />
Location description: Cruz Bay, downtown<br />
Collection date: 2005-11-14<br />
Collector: Wetterer, J.<br />
<br />
Location: 18.348, -64.726<br />
Location description: Carolina, 1 km up 20<br />
Collection date: 2005-11-10<br />
Collector: Wetterer, J.<br />
<br />
Location: 18.352, -64.760<br />
Location description: St John; Cinnamon Bay; moist beach<br />
Collector: Pressick and Herbst 1973<br />
<br />
Location: 18.317, -64.718<br />
Location description: St John; Lamesaur; Croton-Acacia Scrub<br />
Collector: Pressick and Herbst 1973<br />
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To the records above, the following records are being added:<br />
<br />
Location: 18.35261, -64.76818<br />
Location description: Trunk Bay Covered Picnic Area<br />
Collection date: 2017-2<br />
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The ants formed trails along the sides of the covered cemented picnic area, as well as nearby areas, where their friable nest mounds are very easily noticed thrusting out from the ground.<br />
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Location: 18.32757, -64.79318<br />
Location description: Car Ferry Parking Lot<br />
Collection date: 2017-2<br />
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The ants formed trails along the sides of the parking lot leading up to the car ferry.<br />
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I surveyed parts of Cinnamon Bay, including the the beach itself and the grounds making up the Cinnamon Bay resort and Campground, and did not find <i>P. megacephala</i> in this area, although I did find another larger <i>Pheidole</i> species.<br />
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Author: A.R. Sunjian<br />
<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-41980473029497658562017-02-04T19:08:00.000-08:002017-02-20T16:54:29.029-08:00How P. megacephala repels Eciton army ant raids<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjbuWMMuu8ctVg0UIT8QMNMpf4ut9qvkDjSgOLrzGDcMtTvzhAlry45wMhAjFCQfc1pRZ6j9zIW7tepH7xneAHaXAM6P8cI_QvKm2m8Z2K0g2rE1YrWOLuhAILRvdFskf6Ev_SX6-656o/s1600/Eciton_burchellii_army_ants.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjbuWMMuu8ctVg0UIT8QMNMpf4ut9qvkDjSgOLrzGDcMtTvzhAlry45wMhAjFCQfc1pRZ6j9zIW7tepH7xneAHaXAM6P8cI_QvKm2m8Z2K0g2rE1YrWOLuhAILRvdFskf6Ev_SX6-656o/s400/Eciton_burchellii_army_ants.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Eciton burchelli</i> army ant.<br />
Image by Alex Wild (from Wikipedia)</td></tr>
</tbody></table>
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There is a certain morbid fascination associated with watching the depredations of various army and driver ants on their hapless prey. The huge colonies of these ants and their mass raids make them formidable predators against most ant colonies. Even the very populous <i>Atta</i> leafcutter colonies, which are normally immune to most army ant species, can be overwhelmed by army ants specialized against them, such as <i>Nomamyrmex esenbecki.</i> (Swartz M, 1994)<br />
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Some invasive ant species too are prey to army ants. Colonies of the little fire ant <i>Wasmannia auropunctata</i> for example, are devastated by the army ant <i>Neivamyrmex compressinodis </i>and perhaps some other<i> Neivamyrnex </i>species (J. Le Breton et al, 2007).<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_kGZNAuy7nr3f0PduvVx39YI5dM3FJ7jN7AR5Ys9biFR3oCzff7Qft4dllKKyxRokU-aIgkykpV8gXe0xL3YjPrxJw8zVjtoQ40LLel9UBPZ-ygAXwFHueH-Gt8E4xnEie7b9dCj2Kyw/s1600/littlefireant1.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="130" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_kGZNAuy7nr3f0PduvVx39YI5dM3FJ7jN7AR5Ys9biFR3oCzff7Qft4dllKKyxRokU-aIgkykpV8gXe0xL3YjPrxJw8zVjtoQ40LLel9UBPZ-ygAXwFHueH-Gt8E4xnEie7b9dCj2Kyw/s400/littlefireant1.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Wasmannia auropunctata</i>. <br />
Image from Hawaii Invasive Species Council (HISC).</td></tr>
</tbody></table>
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<i>Solenopsis geminata</i> colonies also fall prey to <i>Eciton</i> and <i>Labidus</i> army ant raids, although most times the fire ants manage to abscond from their nest ahead of the invasion (Perfecto 1992).<br />
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<i>Pheidole</i> ants as a rule tend to be favored prey not only for the larger <i>Eciton</i> army ants, but for the smaller <i>Neivamyrmex</i> ants as well, probably due to their smaller colony populations and ubiquity in tropical and subtropical environments. This has resulted in some very interesting social behavior, including the classic discovery of enemy specification by E.O. Wilson (Wilson E.O, 1976).<br />
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However, unlike other <i>Pheidole</i> ants, <i>P. megacephala</i> with its huge unicolonial societies and extremely aggressive workers might pose a problem for even the most voracious army ants.<br />
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Indeed, <i>P. megacephala</i> in Africa actually preys on the formidable <i>Dorylus</i> driver ants, and a study done by Dejean et al (2014) reveals that this invasive ant is able to handle the New World <i>Eciton</i> army ants as well.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiM5nMF4nRnP-Olc9XMCO-YHcKkmWa8zu3JwPgZMpfwcRbC11AvOlIRnV7llpsBTwJRBYcNlfhKAIqcDaGrqwe4HqlKBRcsTprfTPAPcAIyEMD7-MQgszKCPhnv0UdllkjtMRCx0BPO18M/s1600/megacephala4-XL.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="266" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiM5nMF4nRnP-Olc9XMCO-YHcKkmWa8zu3JwPgZMpfwcRbC11AvOlIRnV7llpsBTwJRBYcNlfhKAIqcDaGrqwe4HqlKBRcsTprfTPAPcAIyEMD7-MQgszKCPhnv0UdllkjtMRCx0BPO18M/s400/megacephala4-XL.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">P. megacephala minors prey on Dorylus worker.<br />
Image courtesy of Alex Wild. <a href="http://www.myrmecos.net/">Click to go to Myrmecos.net</a></td></tr>
</tbody></table>
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The researchers observed interactions between <i>P. megacephala</i> and two <i>Eciton</i> species in Puerto Morelos, Mexico. They analyzed 24 raids by <i>Eciton burchelli</i> on a <i>P. megacephala</i> colony, and 11 raids by <i>Eciton hamatum</i>.<br />
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According to the researchers, the incoming raids were met by fierce resistance from the <i>Pheidole,</i> with many army ants spread-eagled by the defenders as the raiders pushed inward through the colony entrances. In addition to those being killed in the melee by the <i>P. megacephala</i>, outgoing army ants after seizing booty or escaping from the <i>Pheidole</i> nest were in turn attacked by their own nestmates!<br />
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During each raid, an average of 1,869 <i>E. burchelli </i>workers were killed by their own colony members, while an average of 1,380 <i>E. hamatum</i> army ants were killed by their fellow nest mates. These casualties make up a not insubstantial 0.4 % and 0.55% of the total estimated population of typical <i>E. burchelli</i> and <i>E. hamatum</i> colonies, and the loss of outgoing raiders stifled the invasion of the <i>P. megacephala</i> nests.<br />
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The researchers noted that it seems as if an aqueous compound(s) was transferred to the attacking army ants as they battled <i>P. megacephala</i>, which caused their colony mates to attack them instead, and thus indirectly abort the raid.<br />
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Given the high mortality suffered by the army ants, and since <i>P. megacephala</i> is not native to the neotropics and thus a "novelty" to the native ants there, it would be interesting to speculate on whether the army ants might later evolve mechanisms to avoid raiding such nests, just as they avoid other heavily protected species like <i>Atta</i> leafcutters.<br />
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For more information on this interesting study, consult the paper:<br />
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Dejean Alain, Azémar Frédéric, Roux Olivier. (2014) "An invasive ant species able to counterattack marabunta raids." Comptes rendus biologies 337 (7-8): 474-9.<br />
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Abstract:<br />
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<i>In the Neotropics where it was introduced, the invasive ant Pheidole megacephala counterattacked raids by the army ants Eciton burchellii or E. hamatum. The Eciton workers that returned to their bivouac were attacked and spread-eagled and most of them killed by their outgoing colony mates. Little by little the zone where returning and outgoing Eciton workers encountered one another moved away from the Pheidole nest which was no longer</i><br />
<i>attacked, so that most of the colony was spared. Using a water-based technique rounded out by bioassays, we show that Pheidole compounds were transferred onto the Eciton cuticle during the counterattacks, so that outgoing workers do not recognize returning colony mates, likely perceived as potential prey. Because P. megacephala is an introduced African species, this kind of protection, which cannot be the result of coevolutive processes,</i><br />
<i>corresponds to a kind of by-product due to its aggressiveness during colony defence.</i><br />
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Dejean Alain, Azémar Frédéric, Roux Olivier. (2014) "An invasive ant species able to counterattack marabunta raids." Comptes rendus biologies 337 (7-8): 474-9.<br />
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J. Le Breton, A. Dejean, G. Snelling, J. Orivel. (2007) Specialized predation on Wasmannia auropunctata by the army ant species Neivamyrmex compressinodis. J Appl Entomol, 131, pp. 740–743<br />
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PERFECTO I. Observations of a Labidus coecus (Latreille) underground raid in the central highlands of Costa Rica. Psyche. 1992;99:214-22<br />
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Swartz, M. (1994) Predation on an Atta cephalotes colony by an army ant, Nomamyrmex esenbeckii. Biotropica 30(4):682-684<br />
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Wilson EO. (1976) The organization of colony defenses in the ant Pheidole dentata Mayr (Hymenoptera: Formicidae). Behavioral Ecology and Sociobiology 1: 63–81.BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-56742344355665282982017-02-03T13:08:00.002-08:002017-02-20T16:54:48.771-08:00Butterfly effects: Acacias, Elephants, and the Ants that guide their relationship<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEoWwwRcotOMKO3P0Cie3cpBwpomrYAc02N0FnUjjaBG4TUBRuqnw73CWb06u9kpJMO09_a-n_rCy2m4cRLdhvAu2hsekpzqUNpTFLF11S03Z4s7tEoo2GcgGRMZJSEQHX6vrKpoO2sfY/s1600/crematogaster2.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="261" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEoWwwRcotOMKO3P0Cie3cpBwpomrYAc02N0FnUjjaBG4TUBRuqnw73CWb06u9kpJMO09_a-n_rCy2m4cRLdhvAu2hsekpzqUNpTFLF11S03Z4s7tEoo2GcgGRMZJSEQHX6vrKpoO2sfY/s400/crematogaster2.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Acacia drepanolobium and Crematogaster nigriceps. <br />
Image courtesy of Pharaoh han</td></tr>
</tbody></table>
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It is sometimes difficult for people to imagine how the activities of minute creatures like ants can have major effects at the meter scale world, but a paper I read recently demonstrates such a process clearly.<br />
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In Kenya there is a tree called the whistling thorn acacia (Vachellia drepanolobium – formerly Acacia drepanolobium), an iconic shrub of the East African savanna that grows to 6 meters tall and is covered with intimidating thorns, some of which have bulbous bases and are called domatia.<br />
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The bulbous bases are hollow, and house symbiotic ants that protect the tree from browsing by herbivores. The tree also provides the resident ants nutrition in the form of sugary secretions from glands at the base of their leaves.<br />
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<iframe allowfullscreen="" class="YOUTUBE-iframe-video" data-thumbnail-src="https://i.ytimg.com/vi/s3blzcbll7Q/0.jpg" frameborder="0" height="266" src="https://www.youtube.com/embed/s3blzcbll7Q?feature=player_embedded" width="320"></iframe></div>
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The tree houses one of four different species of ants: <i>Crematogaster sjostedti</i>, <i>C. mimosae</i>, <i>C. nigriceps</i>, and <i>Tetraponera penzigi</i>, all of which swarm out to attack browsing animals with varying degrees of effectiveness, though the overall efficacy of the ants as guardians is quite high. As shown in the youtube video above, acacias with no ants tend to do very badly when large herbivores are present.<br />
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This relationship between the acacias, herbivores like elephants, and the ants that guard the acacias has recently been disrupted by the appearance of <i>Pheidole megacephala</i> (BHA) in the Laikipia region of Kenya within the last 10-15 years. In a research paper in the journal Ecology, Corinna Riginos and her colleagues moved complete trees along with their resident ants from uninfested locations to areas infested with BHA.<br />
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Almost immediately, BHA discovered the new trees and started moving up the trunk, only to be met in force by the aggressive <i>Crematogaster</i> species, who streamed down to meet and repel the invaders. In all such cases, however, the resident ants were fairly quickly pushed up the trunk and soon vanquished, their nests looted and any remaining adult defenders killed if they could not escape. The only exception was in trees with the <i>Tetraponera</i> ants, who instead of meeting the invaders head on, instead retreated into their domatia where the BHA could not get to them.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJkRz_c7aWGLA5qIAFIgUPC3u8YIBXQcbj_VjXDhH5MUnMaxXZyymn-A2gaNzMgqVzNPyhPp6JyIOF8o4Ookh_xUyL0FquJ0sXziSm2_KmbxlITirEgYZ0fZWNCEkTEb0ABj_uaFBy9O0/s1600/Vachellia_drepanolobium_seed_pods.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJkRz_c7aWGLA5qIAFIgUPC3u8YIBXQcbj_VjXDhH5MUnMaxXZyymn-A2gaNzMgqVzNPyhPp6JyIOF8o4Ookh_xUyL0FquJ0sXziSm2_KmbxlITirEgYZ0fZWNCEkTEb0ABj_uaFBy9O0/s400/Vachellia_drepanolobium_seed_pods.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Acacia seedpods. Image courtesy of Chr. Kooyman</td></tr>
</tbody></table>
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The researchers found that even 30 days after the invasion, with BHA patrolling throughout the entire tree, the <i>Tetraponera</i> ants managed to eke out an existence. Foragers who came out lay still and did not fight BHA ants who came to them, and the BHA ants did not seem to consider them to be hostile. In fact, the density of <i>Tetraponera</i> colonies significantly increased in invaded areas, due to the removal of their <i>Crematogaster</i> competitors.<br />
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Unfortunately for the acacia trees, the <i>Tetraponera</i> is the least effective defender against encroaching herbivores, and BHA itself does not attack large mammals who decide to browse on the plant. This resulted in significant damage to the host acacias, with the researchers finding up to a seven fold increase in the number of trees catastrophically damaged by elephants in invaded areas versus those trees in uninvaded locations. This damage to the trees due to the disruption of the mutualism between plants and ants has the potential to cause significant changes in the dynamics of the savanna ecosystems where this acacia is dominant.<br />
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The relevant paper is:<br />
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Riginos, C., M.A, Karande, D.I. Rubenstein & T.M. Palmer. 2015. Disruption of a protective ant–plant mutualism by an invasive ant increases elephant damage to savanna trees. Ecology 96:654-661.3<br />
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The abstract of the paper:<br />
<br />
<i>Invasive species can indirectly affect ecosystem processes via the disruption of mutualisms. The mutualism between the whistling thorn acacia (Acacia drepanolobium) and four species of symbiotic ants is an ecologically important one; ants strongly defend trees against elephants, which can otherwise have dramatic impacts on tree cover. In Laikipia, Kenya, the invasive big headed ant (Pheidole megacephala) has established itself at numerous locations within the last 10-15 years. In invaded areas on five properties, we found that three species of symbiotic Crematogaster ants were virtually extirpated, whereas Tetraponera penzigi co-occurred with P. megacephala. Tetraponera penzigi appears to persist because of its non-aggressive behavior; in a whole-tree translocation experiment, Crematogaster defended host trees against P. megacephala but were extirpated from trees within hours. In contrast, T. penzigi retreated into domatia and withstood invading ants for >30 days. In the field, the loss of defensive Crematogaster ants in invaded areas led to a five- to seven-fold increase in the number of trees catastrophically damaged by elephants compared to un-invaded areas. In savannas, tree cover drives many ecosystem processes and provides essential forage for many large mammal species; thus, the invasion of big-headed ants may strongly alter the dynamics and diversity of East Africa’s whistling thorn savannas by disrupting this system’s keystone acacia-ant mutualism.</i><br />
<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0tag:blogger.com,1999:blog-2064349664851462732.post-11011288700743198702017-02-02T18:58:00.004-08:002018-03-16T09:46:25.465-07:00My first encounter<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhomqziNJvWZp75NpOSrD53BFuMhqRhyphenhyphennAlWci4Su8gnVy0M-nbMvjqVq1LJUzTGOMOo7zXhmLWrzFLdO64zF9XLo9RDCdljRj-6iwGR9qd_aznr5hdMZV6-C1NNAw5SyqEuVYC0EqHp3M/s1600/bigheaded_ant13.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="278" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhomqziNJvWZp75NpOSrD53BFuMhqRhyphenhyphennAlWci4Su8gnVy0M-nbMvjqVq1LJUzTGOMOo7zXhmLWrzFLdO64zF9XLo9RDCdljRj-6iwGR9qd_aznr5hdMZV6-C1NNAw5SyqEuVYC0EqHp3M/s400/bigheaded_ant13.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Photograph by R.H. Scheffrahn, University of Florida</td></tr>
</tbody></table>
<br />
I had known about this ant of course.<br />
<br />
Ever since I was perhaps sixteen I had read about its status as an exotic species, one which had profoundly negative effects on native populations of animals and plants.<br />
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And yet I did not get to see them first hand until the late 1980s, when I visited the island of Kauai in Hawaii. I wrote this in a journal during my stay there:<br />
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<i>This Pheidole species dominates the local ant fauna and seems to thrive almost anywhere: from the sandy beaches near our resort, to the rugged, stony sides of the island's mountains.</i><br />
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<i>The major workers are extremely pugnacious, and the minors only a bit less so. The majors do not feed at mayonnaise baits, but rather move randomly around them, occasionally rushing threateningly at passing minor workers.</i><br />
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<i>The introduction of a formicine ant into a congregation of minor workers at a bait elicited an immediate response. The intruding ant was quickly immobilized by the minor workers, who bit and held onto its legs and antennae. Some two minutes later, a relatively large number of major workers rushed into the scene and started moving all around the place.</i><br />
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<i>This Pheidole is one of the most aggressive extirpators that I have seen. However, due to their relatively small size, they are sometimes not very efficient at acquiring moving "baits".</i><br />
<i><br /></i>
<i>For example, the black formicines were very quickly and efficiently dragging a large dead wasp to their nest. I took the wasp by the wings and dropped it near some P. megacephala ants, and the formicines immediately began dragging the wasp away again, even before the Pheidole could react. I did this a couple of times more, and at last some minors managed to grab good holds on the wasp legs and prevented the formicines from dragging it away.</i><br />
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<i>The minors were incredibly aggressive, given the fact that they were only a third the size of the very much faster formicine. They grabbed onto the appendages of the black ants whenever the opportunity arose, and let go only when squirted with formic acid. And since the P. megacephala ants are very efficient mass recruiters, the flood of workers that soon followed effectively drove the formicines away.</i><br />
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<i>In order to do justice to the black ants, I placed gobs of mayonnaise near their home nest, at the base of a large pot, about 1 meter away from the scene of the first tussle. The bait was soon covered with black ants.</i><br />
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<i>Just before I left, I noticed a single P. megacephala scout near the black ants' home, and when I came back 20 minutes later, the Pheidole ants had claimed all the mayonnaise gobs near the black ants' nest. Major workers were moving all around the baits as well.</i><br />
<br />BanyanWandererhttp://www.blogger.com/profile/11670269057329577541noreply@blogger.com0