Paternal Care in Giant Water Bugs

The earliest known brood care in insects

“…Large eggs often provide more nutrient reserves for offspring, which is conducive to juvenile survival in harsh environments [39]. However, the cost of laying large eggs is a longer hatching period, and more importantly, surface/ volume ratio of large egg is low, which adversely impacts gas exchange between water and eggs, making it more difficult for eggs to obtain adequate oxygen [40,41]. Because water oxygen are crucial and mutually restrictive environmental factors for the embryonic development of aquatic arthropods, some aquatic arthropods evolved extraordinary behavioural adaptations for aerating and hydrating eggs might be related to their large eggs that must rely on passive diffusion of oxygen [2,35].…”

“…Because water oxygen are crucial and mutually restrictive environmental factors for the embryonic development of aquatic arthropods, some aquatic arthropods evolved extraordinary behavioural adaptations for aerating and hydrating eggs might be related to their large eggs that must rely on passive diffusion of oxygen [2,35]. For example, the basal giant water bugs in the lethocerines (emergentbrooders) periodically supply water to the egg mass on the sites of oviposition (commonly emergent aquatic vegetation) [35,[41][42][43]; and belostomatines (back-brooders) even evolved brooding behaviour wherein males carry a clutch of eggs laid by the females on their backs until hatching to prevent them from desiccation and drowning [41,43,44]. The same principle is reflected in some extant water boatman species that lay eggs upon the exoskeletons of freshwater crayfish, especially the gills and first abdominal pleurite where there are the best chances for aeration, relying on the current of flowing water [29,45].…”