Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom.
Am Nat. 2010 Aug;176(2):212-26. doi: 10.1086/653661.
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 287 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 that in 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.
昆虫的亲代抚育广泛而多样，但它对生物史的影响从未被比较性地测试过。我们使用原始数据和文献数据，在 287 种昆虫物种的系统发育中，针对不同的亲代抚育模式，测试了关于卵大小、卵数（终生繁殖力）和体型的预测。生命史理论以及来自变温动物的比较和种内证据表明，亲代抚育应该选择更大、更少的卵，但卵大小和终生繁殖力的种间比例可能取决于抚育是提供食物（取决于后代的生存密度）还是仅仅是保护（与后代的生存密度无关）。出乎意料的是，亲代抚育模式之间的卵大小无法区分，仅与体型相关。这驳斥了亲代抚育下卵大小进化的大多数理论。终生繁殖力根据亲代投资的不同而不同——在没有照顾和保护的情况下呈正相关，这与大多数变温动物一样，但在提供食物的情况下呈负相关。在提供食物的昆虫中，生殖分配与哺乳动物和鸟类相似，也与具有强制性提供食物的昆虫相似。我们提出，多个后代的代谢需求与物种体型的比例必须比亲代的提供食物的能力更陡峭，从而导致体型较大的雌性产卵较少。这些模式为更全面地理解亲代抚育和生活史奠定了基础。
