Summer Dormancy in Adult Agabus disintegratus (Crotch) (Coleoptera: Dytiscidae) in Dried Ponds in California
Summer Dormancy in Adult Agabus disintegratus (Crotch) (Coleoptera: Dytiscidae) in Dried Ponds in California
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加利福尼亚州干池塘中成年阿加布斯瓦解体（胯部）（鞘翅目：龙蛔科）的夏季休眠
DOI：
10.1093/aesa/80.2.267
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
K. Hagen
中科院分区：
文献类型：
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作者：
Richard Garcia;K. Hagen
在百密草（Cynodon dactylon L.）根土界面中发现了处于休眠状态的成虫水甲虫Agabus disintegratus (Crotch)；雀稗（Paspalum dilitatum）；普通香蒲；和硬茎芦苇，Scirpus acutus (Muhl.)，于1985年春末和夏末从加利福尼亚中央山谷的干水禽避难所池塘中捕获。在谷草草皮、谷草草皮或植被贫瘠的地区均未发现甲虫。在夏季灌溉两次的田地中，撕开百慕大草草皮并将碎片通过筛子发现，每600平方厘米草皮表面积上的甲虫数量高达10.3只。捕获的成虫从未在野外或实验室观察到飞行，但在开放的容器中非常活跃。放在松散土壤碎片上的甲虫迅速爬到下面，静止不动。在实验室中保存的甲虫的存活率表明，它们能够在没有水或食物的情况下存活超过5个月。从春末到冬末采集的雌性解剖表明，它们一直没有交配，没有卵母细胞发育，但有相对较大的脂肪储备，直到夏末田地被淹没一段时间后。交配和卵子发育是在10月下旬首次观察到的。湿地植物根系中成虫的节日休眠状态似乎是一种“强制性”的想象滞育，以使繁殖与秋季淹没同步。我们认为这种类型的滞育是首次报道的昆虫滞育。
Adult dytiscid water beetles, Agabus disintegratus (Crotch), were recovered in a dormant state from the root soil interface of bermudagrass, Cynodon dactylon L.; dallisgrass, Paspalum dilitatum (Poir); common cattails, Typha latifolia L.; and hardstem bulrushes, Scirpus acutus (Muhl.), during the late spring and summer of 1985 from dry waterfowl refuge ponds in the central valley of California. Beetles were not found in sod of millet, Panicum miliaceum L., or in areas barren of vegetation. Tearing apart bermudagrass sod and passing the debris through sieves revealed populations of up to 10.3 beetles per 600 cm2 surface area of sod in fields irrigated twice during the summer. Captured adults were never observed to fly either in the field or laboratory, but were very active in open containers. Beetles placed on loose soil debris quickly crawled beneath it and became still. Survivorship of beetles held in the laboratory showed that they were capable of living for more than 5 mo without water or food. Dissection of females collected from late spring to midwinter indicated that they remained unmated and without oocyte development, but with relatively large fat reserves, until some time after the fields were inundated in late summer. Mating and egg development were first observed in late October. The estival dormant state of adults in the root systems of wetland plants appears to be an “obligatory” imaginal diapause to synchronize reproduction with autumnal inundation. We believe this type of diapause to be the first reported for a dytiscid.