bug_boy_jack 的最愛

Just for interest, added cycad seeds being sorted . Nobody seems to know who brought them in or where they came from, but many of the seeds have similar holes, similarly empty. None of our cycads have cones now, so thinking this beastie came in with the seeds.

Dead Nomamyrmex army-ant workers collected from a mound of the leafcutter ant Atta texana. The workers here are under ethanol, and images are therefore somewhat blurry.

Nomamyrmex are specialist predators of Atta, but they prey also on other ant species. This here is most likely Nomamyrmex esenbeckii, but I identify only to genus because there have been suggestions that Nomamyrmex hartigii may also occur in south Texas. In my nearly 25 years surveying ants in south Texas, I have seen live Nomamyrmex only once, 9 years ago at the Mesquite Trail at the visitor center at Laguna Atascosa NWR (near the cemetery at the northern loop of the Mesquite Trail; 28. November 2013, ≈12:15PM; UGM131128-01) .

I recently started to search for dead Nomamyrmex on Atta texana mounds that look disturbed and "disheveled", perhaps because they were recently raided by Nomamyrmex. This here is the first find of Nomamyrmex since I started to search the ground on top of such "disheveled" Atta mounds more closely. The dead workers here were dry, and half-embedded & baked into the top soil (sand), so the Nomamyrmex raid on this Atta mound must have occured a while ago, sometime before the last rain here.

See also my below comment added in Feb.2023: "I finally found the time to ID to species, using a microscope and the Watkins 1977 key: Post-occipital sulcus present, therefore esenbeckii"

observation UGM220314-16
elevation 14 meter

Dead Nomamyrmex esenbeckii army-ant major engaged in battle with dead Atta texana worker. I found 6 dead esenbeckii army ants on top of a large Atta texana mound (the 6 dead workers in third photo), and one of these esenbeckii majors had died while battling an Atta texana worker (first 2 photos). I had written before that I started to look for dead Nomamyrmex on top of Atta texana mounds, and this is the second time I found Nomamyrmex army ants associated with Atta texana. I searched during two days about 40 Atta texana mounds carefully for the presence of dead Nomamyrmex, and this is the only Nomamyrmex I found among these 40 Atta texana mounds.

Interestingly, this Nomamyrmex observation today was only about 70 meter distant from where I had found dead Nomamyrmex a year earlier in March 2022, at that time on top of a near-abandoned Atta texana mound (see here https://www.inaturalist.org/observations/108890321). It appears that a single Nomamyrex esenbeckii colony may have hounded the Atta texana at this site repeatedly (maybe continuously?) during the last year.

I used the Watkins 1977 & 1982 keys to ID this to esenbeckii (e.g., post-occipital sulcus present).

elevation 16 meter
observation UGM230209-16