Butterflies Do Not Alter Conspecific Avoidance in Response to Variation in Density
Butterflies Do Not Alter Conspecific Avoidance in Response to Variation in Density
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蝴蝶不会因密度变化而改变同种回避
DOI：
10.1093/icb/icx034
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发表时间：
2017
影响因子：
2.6
通讯作者：
Snell-Rood, Emilie C.
中科院分区：
文献类型：
--
作者：
Jaumann, Sarah;Snell-Rood, Emilie C.
高同种密度与种内竞争水平的增加和对性能的各种负面影响有关。然而，生活史策略的改变可以弥补其中的一些影响。例如，在拥挤的环境中，雌性通常只有较少的后代，但它们可能会在每个后代上投入更多。这种投资可能包括生育更大的后代，花更多的时间照顾亲代，或者对后代的安置做出更挑剔的决定。对于处于相对静止的幼年期的动物来说，竞争的代价可能特别高。雌性或许可以通过在个体生殖决策上投入更多，在远离其他雌性的地方养育幼崽或产卵，来避免这种成本。我们验证了一种假设，即在幼年和成年阶段的同种密度线索会导致生活史策略的变化，包括繁殖和产卵选择。我们预测，与相似的低密度线索相比，在雌性斑蝶幼虫期和成虫期的高密度线索导致产卵时的低繁殖力和更高的同种回避。我们使用2×2因子设计来研究蝴蝶幼虫期和成虫期低密度和高密度对回避行为和繁殖力的影响。我们发现过去关于同比密度的信息并不重要；所有的蝴蝶在产卵期间都表现出相似的繁殖力水平和低水平的同种回避，而不管它们以前的幼虫和成虫经历。这些结果表明p。rapaefemales使用一个固定的,而不是灵活,同种的回避策略产卵决策时,同种的密度和过去的信息对生活没有影响的历史和当前的生殖投资。我们推测，这可能部分是因为过去的同种密度数据不是预测当前密度和竞争水平的可靠线索，因此它不会影响该系统中生活史策略的发展。
High conspecific densities are associated with increased levels of intraspecific competition and a variety of negative effects on performance. However, changes in life history strategy could compensate for some of these effects. For instance, females in crowded conditions often have fewer total offspring, but they may invest more in each one. Such investment could include the production of larger offspring, more time spent engaging in parental care, or more choosy decisions about where offspring are placed. For animals that have a relatively immobile juvenile stage, the costs of competition can be particularly high. Females may be able to avoid such costs by investing more in individual reproductive decisions, rearing young or laying eggs in locations away from other females. We tested the hypothesis that conspecific density cues during juvenile and adult life stages lead to changes in life history strategy, including both reproduction and oviposition choices. We predicted that high-density cues during the larval and adult stages of femalePieris rapaebutterflies lead to lower fecundity but higher conspecific avoidance during oviposition, compared to similar low-density cues. We used a 2×2 factorial design to examine the effects of low and high conspecific density during the larval and adult stages of butterflies on avoidance behavior and fecundity. We found that past information about conspecific density did not matter; all butterflies exhibited similar levels of fecundity and a low level of conspecific avoidance during oviposition regardless of their previous experience as larvae and adults. These results suggest thatP. rapaefemales use a fixed, rather than flexible, conspecific avoidance strategy when making oviposition decisions, and past information about conspecific density has no effect on life history and current reproductive investment. We speculate that this may be partially because past conspecific densityper seis not a reliable cue for predicting current density and levels of competition, and thus it does not affect the development of life history strategies in this system.