Maternal hatching synchronization in a subsocial burrower bug mitigates the risk of future sibling cannibalism

Abstract

Sibling cannibalism—the killing and consumption of conspecifics within broods—carries a high risk of direct and inclusive fitness loss for parents and offspring. We reported previously that a unique vibrational behavior shown by the mother of the subsocial burrower bug, Adomerus rotundus (Heteroptera: Cydnidae), induced synchronous hatching. Maternal regulation may be one of the most effective mechanisms for preventing or limiting sibling cannibalism. Here, we tested the hypothesis that synchronous hatching induced by maternal vibration in A. rotundus prevents sibling cannibalism. Mothers and their mature egg masses were allocated to three groups: synchronous hatching by maternal vibration (SHmv), synchronous hatching by artificial vibration (SHav), and asynchronous hatching (AH). We then investigated the influence of each hatching strategy on the occurrence of sibling cannibalism of eggs and early‐instar nymphs in the laboratory. No difference in the proportion of eggs cannibalized was observed among the three groups. However, the proportion of nymphs cannibalized was higher in the AH group than in the SHmv group. The difference in the number of days to first molting within clutch was significantly higher in the AH group than in the SHmv group. Junior nymphs were sometimes eaten by senior nymphs. However, immediately after molting, senior nymphs were at a high risk of being eaten by junior nymphs. Our results indicate that synchronous hatching of A. rotundus is necessary to mitigate the risk of sibling cannibalism.

Paternal care regulates the timing, synchrony and success of hatching in a coral reef fish

“…Beyond hatchling age and resulting morphological trade-offs, synchronous hatching in other taxa that do not provide post-hatching parental care allows hatchlings to avoid predation by cannibalistic conspecifics [33], overwhelm predators as they emerge from the nest [60], and form cooperative groups that improve foraging [61]. In neon gobies, males drastically increased hatching synchrony by rapidly hatching all of the embryos in their clutch, transporting hatchlings to the entrance of the spawning shelter and spitting free-swimming larvae into the water column.…”

“…Parents may induce hatching to help their offspring escape embryo stage risks (e.g. [31][32][33]), or to time hatching in relation to the risks and/or opportunities that their offspring will experience post-hatching (e.g. [15,28,34]).…”

Reproductive biology of the encapsulating, brooding gastropod Crepipatella dilatata Lamarck (Gastropoda, Calyptraeidae)

“…dilatata hatching can occur without female presence, it is possible that the female could play a role in aspects of the process, such as synchronization of hatching, allowing the juveniles to exit in a limited period of time [66]. A greater hatching synchronization in the presence of the female has also been described in other species of brooding invertebrates [67,68].…”

Natural enemy defense, provisioning and oviposition site selection as maternal strategies to enhance offspring survival in a sub-social bug

“…If a mother is not capable of selective fertilization or the production of a distinct trophic egg phenotype, she still may be capable of influencing which offspring are eaten by manipulating hatching asynchrony [ 38 ]. Indeed, the lacewing Chrysoperla rufilabris manipulates hatching period to favor greater heterogeneity in hatching times, facilitating higher levels of sibling cannibalism when food resources are scare [ 39 ], whereas hatching asynchrony is maternally manipulated to reduce cannibalism among sibling nymphs in a burrowing bug [ 40 ], or to favor survival of the last produced offspring in a predatory mite [ 41 ]. Alternatively, some species of bugs continue to produce trophic eggs after egg laying has ceased [ 42 ], or even after offspring have hatched resulting in increased nymphal survival [ 37 ].…”