Macivor J Scott, Salehi Baharak
Department of Biology, York University, 4700 Keele Street Toronto, ON M3J 1P3, Canada.
Environ Entomol. 2014 Aug;43(4):1027-33. doi: 10.1603/EN13241. Epub 2014 Jun 23.
Artificial nests (e.g., nest boxes) for bees are increasingly being used to contribute to nesting habitat enhancement for bees that use preexisting cavities to provision brood. They usually incorporate additional nesting materials that vary by species. Cavity-nesting bees are susceptible to brood parasitoids that recognize their host(s) using visual and chemical cues. Understanding the range of cues that attract parasitoids to bee nests, including human-made analogues, is important if we wish to control parasitism and increase the potential value of artificial nests as habitat-enhancement strategies. In this study, we investigated the cues associated with the orientation of the generalist brood parasitoid Monodontomerus obscurus Westwood (Hymenoptera: Torymidae) to the nests of a common cavity-nesting resin bee Megachile campanulae (Robertson) (Megachilidae). The parasitoids were reared from previously infested M. campanulae brood cells and placed into choice trials where they were presented with pairs of different nest material cues. Among different materials tested, we found that Mo. obscurus was most attracted to fresh resin collected directly from Pinus strobus trees followed by previously used resin collected from the bee nest. The parasitoid also attacked other bee species in the same nest boxes, including those that do not use resin for nesting. Our findings suggest that M. campanulae could act as a magnet, drawing parasites away from other bee hosts co-occurring in nest boxes, or, as an attractant of Mo. obscurus to nest boxes, increasing attacks on co-occurring host bee species, potentially undermining bee diversity enhancement initiatives.
用于蜜蜂的人工巢穴（如巢箱）越来越多地被用于改善那些利用现成洞穴来哺育幼虫的蜜蜂的筑巢栖息地。它们通常包含因物种而异的额外筑巢材料。在洞穴中筑巢的蜜蜂容易受到巢寄生蜂的侵害，这些寄生蜂利用视觉和化学线索识别它们的宿主。如果我们希望控制寄生现象并提高人工巢穴作为栖息地改善策略的潜在价值，那么了解吸引寄生蜂到蜂巢的线索范围，包括人造类似物，是很重要的。在这项研究中，我们调查了广食性巢寄生蜂蒙氏单齿小蜂（膜翅目：广肩小蜂科）对常见的在洞穴中筑巢的树脂蜂钟形切叶蜂（切叶蜂科）巢穴的定向相关线索。这些寄生蜂从之前被寄生的钟形切叶蜂幼虫巢室中饲养出来，并进行选择试验，在试验中给它们呈现成对的不同巢材料线索。在测试的不同材料中，我们发现蒙氏单齿小蜂对直接从北美乔松树上采集的新鲜树脂最感兴趣，其次是从蜂巢中采集的用过的树脂。这种寄生蜂还会攻击同一巢箱中的其他蜜蜂物种，包括那些不使用树脂筑巢的蜜蜂。我们的研究结果表明，钟形切叶蜂可能起到磁体的作用，将寄生虫从巢箱中同时出现的其他蜜蜂宿主那里吸引过来，或者，作为蒙氏单齿小蜂对巢箱的引诱物，增加对同时出现的宿主蜜蜂物种的攻击，这可能会破坏蜜蜂多样性增强计划。
