Monthly Archives: April 2012

Spring myrmecophile collecting

Dr. Margaret Thayer and Dr. Al Newton, staphylinid experts from the Field Museum of Natural History, were visiting us at the University of Kansas this past week. Prior to their departure, we decided to try and get a taste of Kansas eastern deciduous forest.

I decided to take this opportunity to look for Deinopsis, but after some time with no sign of the beetles, I quickly switched to myrmecophile collecting.

Geodromicus brunneus is one of the largest and most brilliantly colored species of Geodromicus in North America.

I think this is a female Batrisodes lineaticollis, found with Lasius sp. under bark.

Limulodes paradoxus runs among ant feet.

Limulodes paradoxus with Aphaenogaster ants under a flat stone. These tiny feather winged beetles are blind and occur in the ant nests of several ant species. I have also collected them with Lasius umbratus.

Trichiusa compacta I think. This species I find in small numbers and associated with dry dead wood. This particular individual was sifted from dry tree hole debris.

Ceophyllus monilis with Lasius sp. under a large flat rock. As I lifted the rock over, the ants hastily carried off their aphid livestock.

Ceophyllus monilis is arguably the largest pselaphine species in North America. This enigmatic myrmecophile is quite widespread where host Lasius spp. are present.

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The Dead Crematogaster

Pella planifer

Please enjoy this awesome satanic instrumental by The Dead Weather whilst you awe at this amazing action shot of Pella planifer ravaging a Crematogaster sp.

I ♡ Scydmaeninae

I want to introduce a new paper by Paweł Jałoszyński. This March in Systematic Entomology, Paweł described a new extinct genus and species of clidicine Ant-like stone beetle, ✝Euroleptochromus sabathi together with a phylogenetic analysis of the supertribe Mastigitae. This species is interesting because unlike the previously described fossil clidicine ✝Palaeoleptochromus, ✝Euroleptochromus has an elongate maxillary palpus with a setose process and a genal setose process similar to the extant sister genus Leptochromus.

Leptochromus agilis

Hopefully you can see the genal and palpal setoses processes in the photo above of Leptochromus agilis.

Paweł, in his phylogenetic analysis also sheds light on the enigmatic position of Papusus, a highly unusually staphylinid that has apparently adapted to living in the deserts of Western North America.

Near Owens Lake in California, habitat of Papusus macer

Papusus has been thought to be a member of the tribe Clidicini, but according this new study, Papusus is either the earliest diverging Clidicini or sister to Leptomastacini + remaining Clidicini. Once staphylinids abbreviated their elytra, biologically, it appears that ability to adapt to arid environments were lost. Presumably the rate of water loss increased with the exposure of the abdominal dorsal surface. Given this, the arid environmental preference of Papusus is intriguing and divergent adaptive regimes may be responsible for poor resolution in phylogenetic placement of the genus – based on morphology.

I think that this is an impressive beginning to elucidating the evolutionary history of the Masitigiate – so so exciting, I love scydmaenines, and their congruent morphology with pselaphines is spectacular. But, I do believe that several pertinent questions persist:

  • What, if any, are the adaptive adaptive advantages of the setose maxillary and genal processes? Prey capture?
  • Is the  phylogenetic placement of Papusus based on morphological evidence accurate? Could the adaptive evolutionary changes, induced by the unique environmental pressures on Papusus, have complicated the inference into the proper phylogenetic placement of the genus within the Mastigitae?
  • Are the branch length estimates based on morphological data precise? If we were to include molecular data for the extant taxa, would we get a different view on evolutionary history of the Mastigitae?
  • Finally, would divergence time estimates of the Mastigitae represent a congruent portrayal of biogeographical history?

Oh, and here’s the reference to the paper:

Jałoszyński, P. 2012. Description of Euroleptochromus gen.n. (Coleoptera, Staphylinidae, Scydmaeninae) from Baltic amber, with discussion of biogeography and mouthpart evolution within Clidicini. Systematic entomology, 37(2): 346-359.

Spiders that live with ants?

As a ridiculously early spring was establishing itself here in Lawrence, Kansas, I noticed a Formica colony reopening its nest in front of my door. I searched around the house for stones and the sort, and came up with a couple bricks and a large rock which I then used to cover up the newly opened nest entrance. Soon the ants reopened the nest underneath the bricks and rock. Now lifting these nest entrance covers reveals a large area of nest – this is a commonly employed technique when collecting for myrmecophiles.

A myrmecophilous linyphiid spider sucking a collembolan dry.

To my surprise, for several weeks now, I have been consistantly picking up this species of what I think is a spider in the family Linyphiidae. My series consists mostly of females, but also includes males and juveniles. When threatened, some of them have been observed to run into the nest, and as you can see from this picture, they appear to at least partially feed on the ant-symbiotic collembolan Cyphodeirus albinus. The collecting has slowed down a little as of late, but I hope to get a nice series that lends weight towards a myrmecophilous life style and aids in identification down the road.

Anyone know of people that might have the expertise toidentify this spider?

Nebria

Nebria sp.

Found amongst cobble at a river bank. Jedidiah Smith State Park, California.

Nebria diversa

Found under debris on a beach. Pistol River State Scenic View Point, Oregon.

Fig-fig wasp mutualism is getting even more complex

I don’t think anything in biology requires as much time and patients as do behavioral studies do. It’s still a manageable task when you’re dealing with mammals since we undoubtedly experience the world similarly. In contrast, little creatures, like insects, experience the environment very differently, rendering natural history observations challenging.

In light of this, it was delightful to receive an email this morning, informing me of a new study on the behavior of fig rove beetles:

Frank, J. H. & H. Nadel. 2012. Life cycle and behaviour of Charoxus spinifer and Charoxus major(Coleoptera: Staphylinidae: Aleocharinae), predators of fig wasps (Hymenoptera: Agaonidae). Journal of Natural History, 46(9-10): 621-635.

The genus Charoxus are a truly fascinating genus of rove beetles, that I think really bring home how ecologically diverse the rove beetles can be. Charoxus are large aleocharine staphylinids (~ 3 mm) with large anteriorly directed mandibles and a cylindrical body, presumably adapted for squeezing into figs and feeding on fig wasps inside.

Figs themselves are pollinated and parasitized by various groups of parasitic wasps; some of these fig-wasp relationships being mutualistic . For fig-pollinating Agaonidae wasps, the females bite their way through the fruit’s ostiole, which essentially shuts out all other visitors – parasitic wasps, therefore, must drill through the fruits exterior. Agaonidae wasps reproduce and mate within the fruit and males open a passageway out of the fruit, where the female wasps exit and Charoxus individuals enter. By now (fig fruit stage D), many of the wasps have left but there is enough of a fauna left that Charoxus are able to almost complete an entire life cycle inside the figs. Charoxus adults lay several eggs within a formally parasitized fig flower and the 3rd instar larvae drop to the ground to pupate, with essentially all necessary feeding appearing to occur within the fig fruit.

Figs themselves are en ecologically important element of many subtropical and tropical biomes. The trees themselves often live parasitically on other plants, and the fruits are important food sources for vertebrates. But to scale this ecological prominence down to the efforts of minute mutualistic wasps, and to further expand this ecological interaction to parasitoids and predators of fig-wasps blows my mind. Charoxus truly adds another element of complexity to the fig and fig-wasp mutualist story.

Cremastocheilus

Cremastocheilus are a myrmecophilous genus of cetoniine scarabs, endemic to the New World. Larvae develop in soil adjacent to host nests, and the adults feed on larvae and pupae of host ants. Adults often congregate on open sandy ground to mate. They also have trichomes, most commonly at the posterior corners of the pronotum, and ants are attracted to these and will guide the scarabs to their nests, tugging at the trichome tufts.

Cremastocheilus sp., found flying low to the ground in a riparian forest in California. Notice the sand is dry and has a sandy feel to it.

Cremastocheilus sp., excavated with a Formica sp. nest in a decaying log in California.

Possibly due to their intimate life with ants, I often find Cremastocheilus missing distal portions of their tarsi.