State of knowledge of viviparity in Staphylinidae and the evolutionary significance of this phenomenon in Corotoca Schiødte, 1853

Abstract

Viviparity is characterized by the retention of fertilized eggs in reproductive tract of the female. This condition is very common in vertebrates, but relatively rare in invertebrates, including insects. The present work presents a review on viviparity in Staphylinidae, with special attention on genus Corotoca Schiødte, 1853. The genus is composed by six termitophilous species with neotropical distribution, and together with Spirachtha Schiødte, 1853 are only two genera with species confirmed as viviparous in the family. Some other cases are only supposition. Also, it is presented information and discussion on the life cycle of Corotoca species based on dissection of females in laboratory and field observations. During the dissection of females of four species of Corotoca it was observed that each female carries three eggs at the same time. The embryos present asynchronous development: when one is located at apex of abdomen, the other two are at IV segment, on abdomen curvature. These observations are complementary with those obtained in field observation, when the female deposits a larva outside the nest, on the foraging trail of termite Constrictotermes cyphergaster (Silvestri, 1901). The strategy of Corotoca species focused on the immature as dispersing agent is derived and probably favor the fitnees in relation to a hypothetical condition in which the adult is the dispersive agent.

Cumulative species description curve of Corotocini (Aleocharinae, Staphylinidae) and prospects for the future

“…Despite some sporadic observations, only recently researches have invested time in investigating and reasoning about the biology and host-parasite interactions, mainly aimed at the model organism beetles of the Corotoca genus and its termite host Constrictotermes cyphergaster (Zilberman et al, 2019). The studies that deal with elucidating the behavior and social-integration of these beetles could be an interesting way to gather samples, understanding the biology of termitophilous organisms and give a wider picture of the true diversity of these beetles.…”

Mate finding in a mimetic termitophile amidst its host termites

“…Both fertilised and non-fertilised C. melantho females can be found inside C. cyphergaster nests (Pisno et al, 2019;Seevers, 1957). Also, an asynchronous development of oocytes and a small spermatheca in females (Zilberman et al, 2019) points to recurrent matings (Pisno et al, 2019). In males, a complete sequence of developing sperm cells in the testes indicates continuous spermatogenesis, reinforcing the idea of repeating matings.…”

“…Corotoca melantho also depends on the physical structure of the termitarium (Pisno et al, 2019), which may also apply to C. araujoi (Zilberman et al, 2019). After all, both species are viviparous, and that may leave pregnant females more vulnerable and prone to benefit from the sheltered environment of the nest.…”

Parallel evolutionary paths of rove beetle myrmecophiles: replaying a deep-time tape of life

“…The most specialized lineages appear to have experienced selection for modified life histories that channel reproductive investment into few, high-quality offspring. The outcome is manifested in production of giant eggs, each almost filling the female abdomen-a convergent feature of myrmecoid species [95]-as well as remarkable viviparity seen in physogastric termitophiles [96]) (Fig. 3E).…”