Tag Archives: formicidae

A sampling of North American Ants

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If you’ll direct your attention to the top-right of this blog, you should notice a new tab labeled North American Ants. It links to a page intended as a visual survey, at the genus level, of the various ants that inhabit the continent.

The more astute among you will notice a few missing genera. In spite of my best efforts, I have not had an opportunity to take stylized white-background shots of all our myrmecofauna.

The good news is that you can help. If you have access to live workers of any of the missing groups I would greatly appreciate a donation. I am especially embarrassed to have missed Stenamma, Dolichoderus, Leptothorax and Liometopum. Please email me (alwild -at- myrmecos.net) if you can assist, and I’ll repay you with a print of your choosing from the galleries.

One of these ants is not like the other ones…

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Who's that odd ant out?

While in sunny Florida last summer (ah, sunshine! I vaguely remember what that looks like), I spent an hour peering into a nest of little Dorymyrmex elegans. These slender, graceful ants are among Florida’s more charming insects.

Every few minutes, though, the flow of elegant orange insects out of the nest was interrupted by a darker, more robust ant: Dorymyrmex reginicula. Who was this interloper?

Continue reading →

Reader question: who discovered the sex of ant workers?

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maricopa9

A query from the inbox:

Hi, my question is regarding the gender of the worker ants (and the ant queen). As we all know; they are female, however was this discovered many centuries ago or is this a recent discovery?

I plead ignorance.  I know apiculturists had figured out the sex of worker bees in by the late 1700s, and that by the 1800s it was widely accepted that ant workers were also female. But that’s the extent of my knowledge.

So I’m punting to my diligent readers.  Do any of you know who first observed that ant workers are female?

If it quacks like a queen…

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As if butterflies weren’t flamboyant enough already, it seems that some of them actively impersonate queens.

Queen ants, that is.  A report by Francesca Barbero et al in today’s issue of Science documents a clever strategy employed by a European butterfly, the Mountain Alcon Blue  Maculinea rebeli, to infiltrate nests of Myrmica schencki.  The immature stages of the butterfly are parasites of ant colonies, and it seems the secret to their success is acoustic mimicry.  The larvae and pupae squeak like queens, eliciting preferential treatment from the workers. Here’s the abstract:

Ants dominate terrestrial ecosystems through living in complex societies whose organization is maintained via sophisticated communication systems. The role of acoustics in information exchange may be underestimated. We show that Myrmica schencki queens generate distinctive sounds that elicit increased benevolent responses from workers, reinforcing their supreme social status. Although fiercely defended by workers, ant societies are infiltrated by specialist insects that exploit their resources. Sounds produced by pupae and larvae of the parasitic butterfly Maculinea rebeli mimic those of queen ants more closely than those of workers, enabling them to achieve high status within ant societies. We conclude that acoustical mimicry provides another route for infiltration for ~10,000 species of social parasites that cheat ant societies.

Sounds of the ants and the butterfly are posted at Science News.   See also commetary by Discover and Not Exactly Rocket Science.

source:  Barbero, F. and J.A. Thomas, S. Bonelli, E. Balletto, K. Schönrogge. 2009. Queen ants make distinctive sounds that are mimicked by a butterfly social parasite. Science 323(Feburary 6): 782-785.

Must we call them meat ants?

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cs

The blue-green iridescence on these Iridomyrmex purpureus workers shines from microscopic sculpturing on the ants' cuticle.

I’ve never taken to the Australian vernacular for one of their most conspicuous insects.  The latin Iridomyrmex purpureus translates as “purple rainbow ant”, referring both to the base color of the body and to the attractive metallic refractions on the cuticle.  But Aussies instead call this colorful species the “meat ant.” Crass by comparison.

On the other hand, it’d probably not do my reputation of masculine bravado much good were I to stroll into a dusty pub in the outback and announce my affection for “purple rainbow ants.”  Crikey! Meat ants it is, then.

A few more pics: Continue reading →

The most-studied ants, an update

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trail1c

My earlier list of the most-studied ant species contained a few omissions.  Here is a more inclusive list:

Ant species sorted by number of BIOSIS-listed publications, 1984-2008

The Top 10 Species Publications
Solenopsis invicta 984
Linepithema humile 343
Lasius niger 250
Formica rufa 167
Atta sexdens 163
Formica polyctena 160
Solenopsis geminata 151
Myrmica rubra 142
Monomorium pharaonis 121
Atta cephalotes 112

Continue reading →

A mysterious tramp: Pheidole moerens

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Pheidole moerens, Louisiana

Pheidole moerens, major worker, Louisiana

Pheidole moerens is a small, barely noticeable insect that travels about with human commerce, arriving without announcement and slipping quietly into the leaf litter and potted plants about town.   As introduced ants go, P. moerens is timid and innocuous- it’s certainly no fire ant.  The species is now present in the southeastern United States, a few places along the west coast, and Hawaii.  Conventional wisdom suggests that P. moerens originated in the Greater Antilles, but even though the ant was first described from Puerto Rico a century ago its exact origin remains uncertain.

The Greater Antilles were a major hub in the global trade of the colonial era, receiving slaves from Africa and shipping sugar north to the distilleries.  A great number of pests had already been carried to the islands by the time European scientists started to fully describe the fauna, so it’s not unlikely that many animals considered native there may have merely used the archipelago as a way-station between their actual origin and their ultimate global distribution.

Now that scientists are equiped with the tools of molecular genetics, we have the ability to determine more precisely the historical routes of spread. It would not take too much work to pin down the origin of P. moerens.  But this ant is just one species of many that are both globally trampy and not particularly troublesome.  Elucidating its origin is thus more an academic than an applied matter, so Pheidole moerens will likely remain mysterious for some time yet.

PH

Pheidole moerens, minor worker, Louisiana

photo details: Canon MP-E 65mm 1-5x macro lens on a Canon EOS 20D
ISO 100, 1/250 sec, f/13, flash diffused through tracing paper