RAPID: Reproductive Behavior of an Unlikely Colonist

火山爆发是地球上最引人注目的自然事件之一。2018年，基拉韦厄火山的喷发引起了全世界的关注，熔岩倾泻在夏威夷大岛的大片地区，冷却后形成了全新的贫瘠土地。第一批在新栖息地定居的生物往往能够远距离分散，繁殖迅速。然而，在夏威夷熔岩流之后，第一个定居的生物是研究很少的熔岩蟋蟀，Caconemobius fori。这只蟋蟀不太可能是第一个殖民者，原因有几个。首先，这些蟋蟀没有翅膀，这意味着它们不能飞得很远，只能走路。这也意味着它们不能像大多数其他蟋蟀物种一样通过唱歌来寻找配偶。其次，人们对熔岩蟋蟀的交配行为知之甚少，但在其近亲中，雌性会咀嚼雄性的腿并消耗它的血液。在像熔岩地这样炎热干燥的环境中，这种液体的损失对雄性来说代价非常高昂。最近基拉韦厄火山的爆发提供了一个前所未有的机会来研究这些蟋蟀潜在的不寻常行为，以及它们如何，或者是否，克服这些挑战，成功地成为第一批殖民者。研究人员将进行行为研究，以了解蟋蟀如何在不会唱歌的情况下找到彼此，并将描述蟋蟀的交配行为和繁殖成功率。调查人员将与火山国家公园的游客和工作人员进行互动，为公园的游客中心制作材料，并制作一部关于重点物种的短片，与公众分享有关这一独特物种的发现。火山爆发是剧烈的，对环境是毁灭性的。2018年，夏威夷岛上的基拉韦厄火山喷发覆盖了近14平方英里的土地，并留下了连续的贫瘠熔岩区域。尽管栖息地荒凉，但在熔岩冷却后的几个月内，它就会被殖民。令人惊讶的是，夏威夷熔岩流的第一个多细胞殖民者不是植物，也不是一般的无脊椎动物，而是蟋蟀，Caconemobius forii，一种可能高度特化的物种。一般来说，新栖息地的第一批殖民者被认为是能够长距离分散和大量繁殖的“杂草”物种。然而，熔岩蟋蟀C. fori挑战了这些假设。这些蟋蟀没有翅膀，这使得它们的传播受到限制，也无法像大多数其他蟋蟀物种那样通过呼叫来定位配偶。此外，近亲物种的交配失败和雄性投资水平也很高——在交配时，雌性会咀嚼雄性的胫刺，并喝下雄性的血淋巴。考虑到熔岩流的极端高温和干燥条件，这对雄性来说代价非常高昂。本研究的目的是：(1)通过野外调查，明确不同年龄的熔岩流对fori生境的利用；(2)检验fori是否利用嗅觉线索进行配偶定位；(3)表征其繁殖行为和成功与否。这项研究的结果将有助于了解第一批殖民者的特征，并促进我们对极端环境下动物交流和繁殖的理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Volcanic eruptions are one of the most dramatic natural events on Earth. In 2018, the eruption of Kilauea captured the attention of the world as lava poured over vast areas of the Big Island of Hawaii and created brand new, barren land as it cooled. The first organisms to colonize new habitats are often able to disperse long distances and breed quickly. However, the first organism to colonize after a lava flow in Hawaii is the poorly studied lava cricket, Caconemobius fori. This cricket is an unlikely first colonist for several reasons. First, these crickets don't have wings, which means that they cannot fly to travel long distances but instead walk. This also means that they cannot sing to find mates like most other cricket species. Second, little is known about the mating behavior of the lava cricket, but in its close relatives, the female chews on the leg of the male and consumes his blood. In a hot, dry environment like a lava field, this loss of fluid could be very costly for males. The recent eruption of the Kilauea volcano provides an unprecedented opportunity to investigate the potentially unusual behaviors of these crickets, and how, or if, they overcome these challenges to succeed as first colonists. The investigators will conduct behavioral studies to understand how the crickets find each other despite not being able to sing, and will characterize the mating behaviors and reproductive success of the crickets. Investigators will interact with visitors and personnel at Volcanoes National Park, develop materials for the visitors center at the park, and develop a short film about the focal species to share findings about this unique species with the general public. Volcanic eruptions are dramatic and environmentally devastating. The 2018 eruption of Kilauea on the Island of Hawaii covered almost 14 square miles of land and left continuous areas of barren lava in its wake. Despite the desolation of the habitat, it is colonized within several months following lava cooling. Surprisingly, the first multicellular colonist of lava flows in Hawaii is not a plant or generalist invertebrate, but is the cricket, Caconemobius forii, a potentially highly specialized species. Generally, first colonizers of new habitat are thought to be 'weedy' species capable of dispersing long distances and breeding profusely. Yet the lava cricket, C. fori, challenges these assumptions. These crickets lack wings, rendering them dispersal limited and unable to call to locate mates like most other cricket species. Furthermore, closely related species show high levels of mating failure and male investment - while mating, females chew on the tibial spur of males and drink the hemolymph. Given the extreme heat and dry condition of lava flows, this should be very costly for males. The aims of this study are to (1) conduct field surveys to clarify C. fori habitat use of lava flows of different ages; (2) test whether C. fori uses olfactory cues for mate localization, and (3) characterize their reproductive behavior and success. The results of this study will provide insight to the characteristics of first colonists, and advance our understanding of animal communication and reproduction in extreme environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.