Termitariophily: expanding the concept of termitophily in a physogastric rove beetle (Coleoptera: Staphylinidae)

Abstract

1. Termitophily in some rove beetles is commonly attributed to the striking termite worker resemblance that is provided by the beetles' hypertrophic ('physogastric') abdomen. However, a termite nest may offer to a termitophile additional benefits, such as a continuously repaired shelter.2. This could apply to Corotoca melantho (Aleocharinae: Corotocini), a viviparous obligatory termitophile staphylinid beetle species. While conferring morphological congruence to its host worker termites, its physogastry may impair mobility, leading to vulnerability and the need for a secure environment. It seems plausible to hypothesise that physogastry in C. melantho would imply in interactions between this termitophile and its host termites as well as its host termitarium.3. This study provides evidence to build such a hypothesis by inspecting the morpho-anatomical reproductive traits of this termitophile. It was found that a gradient of growth stages of embryos and larvae in the oviduct explains physogastry in females while pointing to iteroparity. The asynchronous development of oocytes in females, combined with a full developing sequence of sperm cells indicative of continuous spermatogenesis in males, suggests frequent matings.4. While improving guest-host similarity, physogastry and flightlessness should confer vulnerability to pregnant females, forcing C. melantho to seek close and sheltered environments. These could facilitate the frequent male-female contacts demanded by iteroparity. It is possible, therefore, that physogastry in C. melantho is not only associated with the termites themselves but also with the physical structure of the termitarium. Thus, C. melantho can be hypothesised to be a termitariophile in addition to being a termitophile.

First evidence of wasp brood development inside active nests of a termite with the description of a previously unknown potter wasp species

“…While the former indicates species with association with the host termite colony, the latter indicates species in association with the physical structure of termite nests (i.e., termitarium), not with colony individuals. Recently, this distinction has become clearer with studies in which the authors provide an explanation for choosing either one of the terms (Carrijo et al., 2012; Cunha et al., 2015; Pisno et al., 2019; Rosa et al., 2018). Here, we explicitly follow Kistner’s (1969) original concept of termitophilous associations which defines “termitophiles” as nontermite species that either (a) live inside galleries of host termite nest or (b) have obligatory association with the host termite colony.…”

“…Nests of C. cyphergaster are known to house, in addition to inquiline termites, termitophilous species such as Corotoca melantho (Coleoptera: Staphylinidae), a viviparous rove beetle that shares morphometric (Cunha et al., 2015) and chemical (Rosa et al., 2018) similarity with their host termites. These soft‐bodied, physogastric beetles exhibit reduced body proportions (Cunha et al., 2015) and cryptic habits (Pisno et al., 2019), which often turn detection and behavioral observation into challenging tasks. Yet, with adequate methods, relevant biological information about the group has been revealed, such as mechanisms underlying the nest invasion (Oliveira et al., 2018).…”

“…At the same time, however, nest invaders have developed sophisticated sensory deception mechanisms to go unnoticed by their hosts (Nash & Boomsma, 2008), such as chemical and morphological mimicry. The existence of such mimicry strategies illustrate how evolution may shape nest invaders into true specialists, experts in deceiving the termite builder (examples in Cunha et al, 2015;Oliveira et al, 2018;Pisno et al, 2019;Rosa et al, 2018). The arms race between builder and nest invader, driven by adaptations and counteradaptations from both sides (Dawkins & Krebs, 1979), is thought to produce cases in which the symbiosis is taken to another level, where one of the species-if not both-ends up relying exclusively on the other for survival.…”

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

“…The appearance of viviparity in termitophilous organisms as a possible reproductive strategy could be facilitated by the fact that those species lives inside a termite nest. Pisno et al (2018) stated that the viviparity imply in prolonged periods of vulnerability while the physogastry and wing vestigialization should impair mobility. In this scenario, the adoption of a sedentary life style in termitaria could favour the fitness of this species.…”

The role of mandible morphology in termite inquilinism

“…Morphological traits leading to symbiont defense or host deception are often reported. Arthropods living as macro‐symbionts in nests of social insects, for instance, may have their body modified as a protective shield (Kanao et al., 2016; Cai et al., 2017) or may present striking guest‐host mimetism (Kistner, 1982; Parker, 2016; Pisno et al., 2019).…”