Bayoumy Mohamed H, Michaud J P
Mansoura University, Faculty of Agriculture, Economic Entomology Department, Mansoura 35516, Egypt.
Department of Entomology, Kansas State University, Agricultural Research Center-Hays, 1232 240th Ave, Hays, KS 67601.
J Econ Entomol. 2015 Aug;108(4):1665-74. doi: 10.1093/jee/tov148. Epub 2015 Jun 6.
Egg cannibalism is common in Coccinellidae, but its biological consequences have not been fully explored. We examined egg cannibalism by neonates, fourth instars, and adults of Hippodamia convergens Guerin-Meneville for effects on development, reproduction, and progeny fitness. We also tested female adults for ability to avoid cannibalizing their own eggs and first-instar larvae, and both sexes for changes in cannibalism propensity following mating, all in the presence of ad libitum food [larvae: eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), adults: Schizaphis graminum (Rondani)]. Cannibalism by neonates reduced developmental time and increased male body size. Cannibalism in the fourth instar accelerated pupation and led to the production of eggs that hatched faster, regardless of which parent cannibalized. However, egg fertility was improved only by maternal cannibalism in the fourth instar. Females recognized their own egg clusters, sometimes added eggs to them, and preferentially cannibalized nonfilial clusters. Most gravid females cannibalized a first-instar larva within 30 min, whether filial or not. Adult egg cannibalism was similar for virgin males and females, but declined after mating in males, and increased in females, although it had no effect on fecundity or fertility. Daughters of cannibal pairs were heavier than those of other mating combinations, but offspring of noncannibal parents had the fastest development. Reproductive females appeared to use egg cannibalism to reduce risk for their own eggs, increasing the number cannibalized with the number laid. Thus, egg cannibalism in coccinellids varies with life stage, sex, and reproductive condition, independent of food availability, and benefits are life stage specific.
卵食行为在瓢虫科中很常见，但其生物学后果尚未得到充分研究。我们研究了多异瓢虫（Hippodamia convergens Guerin-Meneville）的初孵幼虫、四龄幼虫和成虫的卵食行为对发育、繁殖和后代适合度的影响。我们还测试了成年雌虫避免取食自己的卵和一龄幼虫的能力，以及两性在交配后食卵倾向的变化，所有实验均在食物充足的情况下进行（幼虫：地中海粉螟（Ephestia kuehniella Zeller，鳞翅目：螟蛾科）的卵，成虫：麦二叉蚜（Schizaphis graminum (Rondani)））。初孵幼虫的卵食行为缩短了发育时间并增加了雄虫的体型。四龄幼虫的卵食行为加速了化蛹，并导致所产的卵孵化更快，无论取食的是哪一方亲本。然而，只有四龄幼虫期的母本卵食行为能提高卵的受精率。雌虫能够识别自己的卵块，有时还会往里面添加卵，并且优先取食非子代的卵块。大多数怀卵雌虫在30分钟内会取食一条一龄幼虫，无论其是否为子代。成年雄虫和雌虫的卵食行为相似，但雄虫在交配后卵食行为减少，而雌虫则增加，不过这对雌虫的产卵量或受精率没有影响。取食卵的亲代所产的子代雌虫比其他交配组合的子代雌虫更重，但非取食卵的亲代的后代发育最快。有繁殖能力的雌虫似乎通过卵食行为来降低自己卵的风险，随着产卵数量的增加而增加取食卵的数量。因此，瓢虫的卵食行为因生命阶段、性别和繁殖状况而异，与食物供应无关，且益处具有生命阶段特异性。
