Trophic egg feeding by queens of two non-army ant doryline genera Cerapachys and Yunodorylus.
Riou Mizuno, Riou Mizuno , Katsuyuki Eguchi , Dang Van An , Weeyawat Jaitrong , Fuminori Ito
Faculty of Agriculture, Kagawa University, Japan.; Faculty of Agriculture, Kagawa University, Japan. ; Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Japan. ; Vietnam National Museum of Nature. ; Natural History Museum, National Science Museum, Thailand. ; Faculty of Agriculture, Kagawa University, Japan.
The ant subfamily Dorylinae contains the true army ant group, which shows the army ant adaptive syndrome, and the non-army ant dorylines. To understand the evolution of the army ant adaptive syndrome, biological knowledge of the non-army ant genera is important, however, their rarity results in little biological knowledge, except for the well-studied species Ooceraea biroi. We studied colony composition and behavior of Yunodorylus eguchii and two species of the Cerapachys sulcinodis group. These two genera are phylogenetically close to the old world army ant genera Dorylus and Aenictus. The two species of the C. sulcinodis group and Y. eguchii showed the following common biological characteristics: (1). Colony size was large, more than thousand workers. (2). Queens were ergatoid. The Y. eguchii queen was the subdichthadiigyne with an elongate abdomen. (3). Reproduction was cyclic, similar to some other doryline ants. (4). Workers frequently laid trophic eggs that were consumed by queens, workers and larvae. (5). The queens fed exclusively on the trophic eggs. The frequency of trophic egg feeding by queens during the egg laying period was remarkably higher than during the non-reproductive period. These results indicate that these species seem to be an intermediate stage in the evolution of the army ant adaptive syndrome. In addition, trophic egg feeding can be an efficient nourishment pathway to queens, especially in a large colony with cyclic reproduction.