A look into the mysterious spongiform tissue found abundantly in the genus Strumigenys.
Strumigenys is an eccentric genus known for its cryptic lifestyle, trap-jaw mandibles (in certain species), and many other quirks, but an often overlooked feature is its spongiform tissue. This structure is found on most species in the genus, and is visible around the petiole and postpetiole. For the longest time, the purpose of spongiform tissue was unclear, but Chu Wang and six other researchers discovered valuable insight into the mystery earlier this year.
Ants rely heavily on chemical communication as do other eusocial insects, and the cuticle—or surface of the exoskeleton—plays a major role in this. Exocrine glands are found across the cuticle, serving to release substances onto the body; sweat glands are an example of this in mammals.
Examination of nineteen Strumigenys species resulted in findings of pores, under which lay gland cells. These cells, along with spongiform tissue tend to be reduced or absent in males. However, larger cells only found at the apex of the petiole and postpetiole are found in both sexes. These glands are dubbed "spongiform tissue glands" and "intersegmental petiole and postpetiole glands" respectively. Similar glands to the former designation have been found in other genera such as Eciton, Protanilla, and Leptanilla, but not of the exact same morphology.
The function of these new glands in Strumigenys is currently unknown, but whatever chemicals are secreted are likely stored or spread over a greater surface area with the help of spongiform tissue. One proposal was that it helps attract prey, but species with different predatory strategies seem to show inconsistent differences in that regard. The structure of the gland cells suggests that pheromones are likely at play.
Read the study to learn more here!
