The video demonstrates some Leptusa (probably pusio) larval behavior. Larvae and adults were collected under oak bark in the fall. I’ve been keeping the larvae in the hopes of seeing whether they spin a cocoon and to confirm the adult association, but because I’ve been keeping them inside and they likely need a period of cold diapause, they were slowly dying off. In the mean time, I took the opportunity to take some videos.
An interesting observation I was able to make was on their “dabbing” behavior using the abdominal defensive gland—originally described by Dettner (1993). The highly pigmented nozzle-like end to the gland is used to dab defensive secretions onto aggressors. I am currently coauthoring a paper where we discuss this morphology as a potential synapomorphy for the homalotine-groups of aleocharines, and I’ll update you guys on it further when it is published.
The brawlers of the aleocharine world – half the males are after the benjamins, the other half are perfectly fine getting what they can get.
Pogonomyrmex harvester ants dump scraps outside their nests.
Pogos at night.
For scavengers, this can be a lucrative place to visit for a meal. Tenebrionidae are frequent visitors. During our trip to TX this past summer, Blapstinus were very diverse and abundant around Pogonomyrmex nest entrances at night.
Blapstinus just eat trash so they’re a benign existence, but nonetheless are not welcome in the eyes of the ants.
This Blapstinus is not welcome.
It’s funny how life works out sometimes. Back in the day, tarsal formula was THE way to classify aleocharines. It’s a nice idea, very numerical and exacting. But, we now know, and this stinging fact is becoming more and more apparent with each additional study, that tarsal formula is super homoplastic and usage needs a bag, not a pinch of salt when considering.
Another addition to the aleocharine tarsal formula collage: 3-4-5!
Fore leg with 3 tarsomeres.
Sometimes in the literature I come across definitions of myrmecophily that are quite restrictive, limiting the phenomenon to the most integrated members of the niche. I strongly think that myrmecophily is a spectrum, ranging into those that are more loosely associated with ants. If we don’t consider the entire spectrum, we miss the entirety of an ecosystem centered around an ant society.
From Texas again. This is Araeoschizus, a tenebrionid. These guys are loosely associated with ants, but they seem to have a tendency to be found with them. I often collect them with a variety of ant species. This trip, I observed them actively following Solenopsis (?) foraging columns at night for the first time. This adds to the complexity of Araeoschizus natural history.
This one’s from Monahans Sand Dunes
I would argue, the most under-appreciated niche among Aleocharinae are the myriad of associations with plants. Naturalists wouldn’t associate aleocharines and probably staphylinids in general as being associated with plants, but of course, the ecologically promiscuous aleocharines have managed to evolve plant-associations multiple times. Although they never really take off in number of species, the ways they associate with plants are rather intriguing.
There are those that eat pollen, such as Platandria, Microlia, Amazoncharis, Polylobus, Oxypodinus, Heterotaxus. Himalusa eats foliage. There are some stranger ones still that are predaceous in the confines of inflourecsens and leaf rolls, such as Charoxus, Ctenopeuca, Heliconandria, and Polycanthode. And then those that seem to be openly predaceous on foliage, like Oligota and
Leucocraspedium Leucocraspedum (thanks go out to Margaret for pointing out the spelling error for the genus).
Below I quickly put together some adaptations that you can find on the fore leg morphology of plant-associated aleocharines.
Adaptations in the fore leg of Aleocharinae associated with plants.
Spines appear to be a popular theme in aiding with grip on a smooth surface, as can be seen in the pollen feeding Amazoncharis and Heterotaxus. Notice that Amazoncharis has stubby modified setae on the ventral surface of its tarsus in addition.
Heliconandria peoechma, on the other hand, lives in the leaf and flower rolls of Heliconia spp. Here, they likely prey on soft bodied organisms and participate in lapping up biofilms for microscopic food items. This species has additional fuzziness on the basal-most tarsomere and a modified tarsal claw. The tarsal claw is ventrally swollen, and has an additional facet which adds surface area.
A new study by Erwin and Zamorano reviews the Neotrpical Lachnophorini, which includes the enigmatic species pictured below. The image was taken by myself on our lab trip to Costa Rica. We were all collecting on a rock face seep for hydrophilids and I captured the imaging thinking, “oh, pretty carabid.” Later the image made its round to Terry and was able to contribute to his recent pub.
Below, Andrew and Crystal are collecting at the seep. I doubt carabids were collected.