Favoritos de mason_s

Consider me dumbfounded, but Atta mexicana are officially established in Santa Cruz Co., AZ. With all of the recent alate observations north of the border (including a few of my own) it has become certain that established populations of this species have pushed further north than Imuris, Sonora. This site had previously been believed to be the northernmost extent of the species circa ~2000, but within the last 25ish years it seems as though the higher elevation habitat north of Imuris has become habitable for this species. Whether or not that is due to climate change, an urban heat island effect in Nogales, or this species adapting to a cooler climate, I am not sure.

As much as I would love to, I cannot take all of the credit for this observation. @ameeds recently made me aware of a BugGuide post by entomologist Salvador Vitanza, where he thoroughly imaged and documented Atta mexicana workers at this exact locality in Nogales, AZ. I was so dumbfounded that within 2 days I was at the locality to verify for myself, and sure enough I found almost exactly what was detailed in the BugGuide Post.
https://bugguide.net/node/view/2306508

Once I confirmed that there were, in fact, Atta workers here, my next task was to locate the colony's "center", the large pile of waste fungus created by these ants above their nesting site. The "nest entrance" detailed by Salvador Vitanza was clearly just a foraging entrance; this species creates underground tunnels from their nest to more fruitful foraging areas - up to 150 meters in any given direction. However, due to the foraging entrance in question having a foraging trail over 100 meters long (BugGuide post says 140m, but I observed the trail fading out at around 105m - trail length likely varies day-by-day). This long trail most likely means that the colony's center was nearby to the foraging entrance. It is worth noting that all foraging activity was on the south side of the street - not a single worker was seen on the north side of the street.

I began my search by exploring the undeveloped land around the property. Unfortunately this area is quite steep, which made it somewhat difficult to survey, but upon searching thoroughly, all I was able to find was an additional foraging entrance underneath a tree located against a backyard wall of the property the original foraging entrance was in front of. I did peer over the wall, but was unable to see any obvious signs of Atta within the backyard of the property.

In the front yard of the property, very close to the original foraging entrance, I noticed 2 additional foraging entrances. One was located in a crack in the walkway , with workers foraging along the side of a concrete barrier for a garden. The second was located in the yard next to a large stone, and had a relatively large and pronounced entrance similar to the one located next to the street. From this entrance a short trail traveled to a Juniper tree, where workers were thoroughly removing plant material and bringing it inside. To see Atta harvesting Juniper so enthusiastically was astonishing to me - I never expected conifers to be a potential food item to Atta.

Given that all four of the foraging entrances I found were centered around this property, and no additional foraging entrances were found away from the property, I suspect the colony's nest is located on the property. I have included a map (last image) of the four foraging entrances and the location of the main long trail.

As a last note on this colony, I do suspect that it is a mature colony. Given the long foraging trails, wide array of plant materials being accepted, and presence of alates in the area, it is likely this colony has been in the area for several years now, and has had the opportunity to spread offspring to other parts of Nogales.

After thoroughly documenting this Atta colony, I explored the rest of the street and a bit of the surrounding area to search for more colonies, but could not find any. I definitely do not expect that this is the only colony in Nogales, AZ, but I was unable to find any additional signs of the species in my limited search. More extensive and widespread searching will definitely be required to find additional signs of this species in Nogales, AZ.

The last note has to do with the male alates found in this observation: https://www.inaturalist.org/observations/179394123
Given that Green Valley is around 35 miles north of Nogales - almost the same distance between Imuris and Nogales, it seems there are only 2 possible explanations. Either those male alates hitchhiked on a truck from Nogales to Green Valley (not impossible considering I-19), or this species extends much further north into AZ than anyone expected. The latter has some merit - previously the higher elevation environment around Nogales was the main barrier preventing Atta from spreading northwards. With this habitat now suitable, I believe there is effectively nothing but time preventing this species from spreading even further north. This may seem like a long-shot, but I suspect that if this population in Nogales is able to persist, we will be seeing Atta in Tucson in the next 30 years.

One live individual, one in-tact dead individual (that I managed to fumble and lose down the nest entrance) and several fragments of elytra observed in the discarded pile of old fungus.

Two shown here- one live (first three photos) and one deceased before I fumbled it. One of the individuals is also shown here: https://www.inaturalist.org/observations/191528251

@cheetolord02 Can you confirm- I think I remember you saying that they are almost always dead when you encounter them in the refuse piles?

With Glen Woolfenden, Ron Smith, and Wendy Hale.

The late, great Glen E. Woolfenden (1930-2007), renowned ornithologist, holding an Indigo Snake that we found after a long day of fieldwork -- note Glen's pants! -- on the Lake Placid Christmas Bird Count. Taken from a scanned slide photograph; the light was fading and I did the best I could with the exposure when I scanned the slide in 2008.

https://en.wikipedia.org/wiki/Glen_Everett_Woolfenden

A very large amount of larvae in nest of Tetramorium caespitum. Easily recognized by the hairless head. Fourth Danish record, and the first from Jutland. On the 21st of April, almost all of the collected larvae had pupated. On the 4th of May, most were fully developed adults.

Squirrel was fighting, biting upper mandible of snake. Then snake did sudden writhe/summersault (maybe just to escape, or maybe to try to get fangs into squirrel). Then squirrel ran away. I couldn’t tell if squirrel had been successfully bitten or if maybe all of the blood was from the snake. If the squirrel dies, hopefully the snake is still able to track it down and eat it.

A 1967 snapshot in time, back before species protection and the TNC preserve. Per Kauffeld-inspired reverential respect, we carefully photographed and released these two specimens---which were found within 100 feet of each other. Golden memories....

I present to you: the largest dragonfly in the world, featuring my face for size comparison! :P Photos simply don't convey its sheer size and bulk but hopefully having something for comparison helps.

Anyway, story time! This guy was flying around erratically for at least an hour and a half since we arrived - I assume due to the missing wing half. I hadn't seen it myself but a couple of my friends had, and it somehow hit me in the side of the head and quickly flew off. :P
Anyway, while we were all chilling around the river, it decided to fly straight into the waterfall (in the background in pic 3) and was promptly swept downstream. What else could I do?? I jumped in and chased after it! 😂
As you can tell from the photos, my swim was successful, and I ended up with the most enormous dragonfly I have ever seen right before me. :P I can't even properly describe how enormously huge it was. And those amazing cerci! I gave it some time to dry off, but being humid tropical Queensland, it wasn't happening very quickly. It was more than happy to sit on my hand and so I wondered if it would prefer somewhere a bit higher and drier :P
So that is how it ended up on my face! As it dried and we were plagued by march flies, the obvious solution was to give him one to eat. He accepted it gratefully and somehow ate the entire thing in a single bite. Hopefully that goes a way into showing just how huge and formidable these guys are! Not content, he then sliced his huge mandibles into my nose -_- and had to be gently prized off. He slowly lapped up blood for a while after but luckily didn't do any more biting! If I squint in the mirror I can still see a faint line there now :P
He sat for about an hour before we had to leave and I left him on a shrub. I hope he was okay with half a wing missing, but there wasn't much else I could do. All in all one of the best experiences of my life! :D

First photo is by Haley Harding because I am incapable of taking selfies :P

Took photo of gray hawk on distant branch, was surprised to see it had an ultra-thin, long snake in it's beak! Another user recommended the ID as brown vinesnake, as we were in its territory/northern range.

These Sonoran Mud Turtles were seen at the wetland, feeding on a very young javelina. There were about one dozen when I first arrived, and most scattered when I approached the water's edge to take photos. At least one turtle was inside the body cavity.