Notes on paternal care and sibling cannibalism in the giant water bug,Lethocerus deyrolli(Heteroptera: Belostomatidae)

Abstract

Males of the giant water bug, Lethocerus deyrolli, care for egg masses on vegetation above the water surface. They supply the developing eggs with water and guard them against predators. In the present study, mechanisms by which paternal care is extended were found. Males were found situated just below the water on the natal substrate (usually a stick), and the first instar nymphs were aggregated around the substrate. When disturbed, the males showed aggressive behavior, threatening the intruder with their forelegs. Nymphs up to 12 h old did not attack the offered sibling nymphs or anuran larvae, which are common prey in the field. The 24 h-old nymphs attacked both prey animals; however, they preferred anuran larvae. Cannibalistic behavior in the nymphs was well developed 72 h after hatching, when the nymphs had already dispersed from the natal substrate. The suppression of sibling cannibalism in younger nymphs would promote the maintenance of tight nymphal aggregations and consequently extend male care in this predatory species.

Desert locust, Schistocerca gregaria, eggs hatch in synchrony in a mass but not when separated

“…In the giant water bug Lethocerus deyrolli, it is the male parent who controls the time of synchronous hatching by spraying water over the egg mass (Ohba 2002). In non-social insects, however, the opportunity for mother-offspring contact is usually restricted to the short period during oviposition, and so, synchronous hatching is often brought about by environmental factors such as temperature (Saunders 2002).…”

Locusta migratoria (Orthoptera: Acrididae) embryos monitor neighboring eggs for hatching synchrony

“…Finally, there are finer, more sophisticated controls of hatching time. For example, water bugs hatch in synchrony from their egg mass in response to water sprayed by the male parent (Ohba 2002). In another example, the eggs of burrow and shield bugs hatch simultaneously in response to vibration produced by the female parent (Mukai et al 2012(Mukai et al , 2014.…”

“…However, little is known about the underlying mechanism of the synchrony. Unlike some subsocial insects, in which egg hatching is facilitated by the parent (Ohba 2002, Mukai et al 2012, most adult insects, including praying mantises and locusts, do not attend to their eggs. Therefore, the embryos in an egg mass likely control the timing of hatching by themselves, especially if synchronous hatching is important for their survival.…”

Kin-selected siblicide and cannibalism in the European earwig

“…Under intense competition, selection may favor aggressive interactions among juveniles (i.e., siblings), which may go as far as siblicide (O'Connor 1978;Mock and Parker 1997). There are many anecdotal reports, suggesting that siblicide (and/or cannibalism) is a common phenomenon in diverse taxa, including insects (Grbic et al 1992;Van Buskirk 1992;Fincke 1994;Osawa 2002;Ohba et al 2006), spiders (Bilde and Lubin 2001), snails (Baur 1992), amphibians (Pfennig et al 1993(Pfennig et al , 1994, fish (FitzGerald and Whoriskey 1992), and mammals (Fox 1975). Importantly, this occurs not only under harsh environmental conditions (Fox 1975) and is not limited to competing juveniles.…”

“…The potential costs due to reduced indirect fitness are expected to generate selection on mechanisms that enables individuals to avoid killing siblings. One mechanism is to avoid encounters with relatives by spreading over space and time via dispersal (Perrin and Goudet 2001;Ohba et al 2006), which is of limited scope in cases when siblings compete in a brood for parental resources. Alternatively, individuals can recognize kin directly (genetically) or indirectly through phenotypic or environmental correlations with kinship (Pfennig 1997;Tang-Martinez 2001).…”