Data from: Parental care trade-offs and life history relationships in insects

Insect parental care is extensive and varied, but its life history implications have never been comparatively tested. Using original and literature data, we tested predictions about egg size, egg number (lifetime fecundity) and body size, under different parental care modes across a phylogeny of 275 insect species. Life history theory and both comparative and intraspecific evidence from ectotherms suggest parental care should select for bigger, fewer eggs, but that allometric scaling of egg size and lifetime fecundity may depend on whether care consists of provisioning (density-dependent offspring survival) or merely guarding (density-independent offspring survival). Against expectation, egg size was indistinguishable among parental care modes, covarying only with body size. This refutes most theory of egg size evolution under parental care. Lifetime fecundity scaled differently depending on parental investment - positively under no care and guarding as in most ectotherms,
but negatively under provisioning. Reproductive allocation in provisioning insects resembled mammals and birds, also groups with obligate provisioning. We propose that the metabolic demands of multiple offspring must scale with species body size more steeply than the parent's provisioning capacity, resulting in larger females laying fewer eggs. These patterns lay the groundwork for a more general understanding of parental care and life history.

昆虫的亲代抚育（parental care）行为广泛且多样，但迄今尚未有研究对其生活史相关影响开展比较性检验。本研究利用原始实测数据与公开文献数据，基于涵盖275种昆虫的系统发育（phylogeny）树，针对不同亲代抚育模式下的卵大小、卵数量（终身繁殖力，lifetime fecundity）以及个体体型相关假说开展检验。生活史理论以及来自变温动物的种内与比较研究证据均表明，亲代抚育会偏向选择产出更大、数量更少的卵；但卵大小与终身繁殖力的异速生长缩放（allometric scaling）关系，可能取决于亲代抚育属于供给型抚育（后代存活呈密度依赖），还是仅为守卫型抚育（后代存活呈密度非依赖）。与预期相悖的是，不同亲代抚育模式下的卵大小并无显著差异，仅与个体体型呈协变关系，这一结果驳斥了多数关于亲代抚育下卵大小演化的理论假说。终身繁殖力的缩放模式因亲代投资（parental investment）类型而异：在无抚育与守卫型抚育条件下，其缩放关系呈正相关，与多数变温动物的模式一致；但在供给型抚育条件下则呈负相关。供给型抚育昆虫的繁殖资源分配模式，与同样依赖专职供给抚育的哺乳类和鸟类相似。我们提出，多只后代的代谢需求随物种体型的缩放斜率必然比亲代的供给能力的缩放斜率更陡，这会导致体型更大的雌性个体产卵数量更少。上述研究结果为更全面地理解亲代抚育与生活史演化奠定了基础。