Gender inequality in predispersal seed predation contributes to female seed set advantage in a gynodioecious species
Gender inequality in predispersal seed predation contributes to female seed set advantage in a gynodioecious species
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DOI：
10.1890/14-1513.1
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发表时间：
2015-05-01
期刊：
影响因子：
4.8
通讯作者：
Brody, Alison K.
中科院分区：
文献类型：
--
作者：
Clarke, Gretel L.;Brody, Alison K.
大多数开花植物是雌雄同体的。然而，在雌雄异株物种中，种群中的一些成员是雄性不育的，只能通过播种繁殖，而另一些成员则通过雄性和雌性功能获得适合度。对于大多数雌雄异株的物种来说，雌性如何弥补雄性功能的丧失仍然是一个悬而未决的问题。在这里，与许多植物一样，适应性差异可能会受到多个物种相互作用的影响。然而，多个物种的相互作用是否会导致性别特异性的适应性差异仍然未知。利用2009-2010年的观测数据，我们量化了两种性别变体的Polemonium foliosissimum的种子集，并询问它是如何受授粉和种子捕食的双翅目predispersal种子捕食者（花蝇科：Hylemya属）。我们评估了种子生产和损失的捕食在27个种群的第一年和第二年在6个种群。女性设置显着更多的种子比雌雄同体在这两年。在我们评估的适合度成分中，包括每株植物的花数、坐果数、种子/果实以及被Hylemya破坏的果实比例，只有果实破坏在性别之间存在显着差异。在一年中，种子/果实和捕食有更强的影响，两性比女性的种子设置。由于predispersion种子捕食者不授粉花，它们的影响可能取决于成功授粉的花，他们产卵。为了研究性别是否在花粉限制和种子捕食和/或其相互作用方面存在差异，在2011年，我们在完全析因设计中手工授粉花并去除种子捕食者卵。两种性别的花粉限制，但他们的花粉限制的程度没有差异。然而，捕食减少种子集更多的雌雄同体比女性。我们发现手花粉和种子捕食之间没有显着的相互作用，手授粉和性别之间没有相互作用。我们的研究结果表明，虽然与传粉者和种子捕食者的相互作用影响生殖成功，花的敌人可以导致性别之间的种子设置的不平等。下一步是了解种子优势如何影响雌性在雌雄异株种群中的长期适应性和持久性。
Most flowering plants are hermaphrodites. However, in gynodioecious species, some members of the population are male-sterile and reproduce only by setting seed, while others gain fitness through both male and female function. How females compensate for the loss of male function remains unresolved for most gynodioecious species. Here, as with many plants, fitness differences may be influenced by interactions with multiple species. However, whether multiple species interactions result in gender-specific fitness differences remains unknown. Using observational data from 2009-2010, we quantified seed set of the two sex morphs of Polemonium foliosissimum and asked how it is affected by pollination, and seed predation from a dipteran predispersal seed predator (Anthomyiidae: Hylemya sp.). We assessed seed production and losses to predation in 27 populations for one year and in six populations for a second year. Females set significantly more seed than did hermaphrodites in both years. Of the fitness components we assessed, including the number of flowers per plant, fruit set, seeds/fruit, and proportion of fruits destroyed by Hylemya, only fruit destruction differed significantly between the sexes. In one year, seeds/fruit and predation had a stronger effect on seed set for hermaphrodites than for females. Because predispersal seed predators do not pollinate flowers, their effects may depend on successful pollination of flowers on which they oviposit. To examine if genders differed in pollen limitation and seed predation and/or their interactive effects, in 2011 we hand-pollinated flowers and removed seed predator eggs in a fully factorial design. Both sexes were pollen limited, but their degree of pollen limitation did not differ. However, predation reduced seed set more for hermaphrodites than for females. We found no significant interaction between hand pollen and seed predation, and no interaction between hand pollination and gender. Our results suggest that while interactions with both pollinators and seed predators affect reproductive success, floral enemies can cause inequality in seed set between genders. The next step is to understand how the seed set advantage affects long-term fitness and persistence of females in gynodioecious populations.