Earlier springs enable High-Arctic wolf spiders to produce a second clutch - supplementary data

Spiders at southern latitudes commonly produce multiple clutches, but this has not been observed at high latitudes where activity seasons are much shorter. Yet the timing of snowmelt is advancing in the Arctic, which may allow some species to produce an additional clutch. To determine if this is already happening, we used specimens of the wolf spider Pardosa glacialis caught by pitfall traps from the long-term (1996-2014) monitoring program at Zackenberg, Northeast Greenland. We dissected individual egg sacs and counted the number of eggs and partially developed juveniles, and measured carapace width of the mothers. Upon discovery of a bimodal frequency distribution of clutch sizes, as is typical for wolf spiders at lower latitudes producing a second clutch, we assigned egg sacs to being a first or second clutch depending on clutch size. We tested whether the median capture date differed among first and second clutches, whether clutch size was correlated to female size, and whether the ...

低纬度地区的蜘蛛通常可多次产卵，但在活动季短得多的高纬度地区，尚未发现此类现象。然而，北极地区的融雪时间正在提前，或可使部分蜘蛛物种额外产下一窝卵。为验证这一现象是否已在北极发生，我们使用了格陵兰东北部扎科本（Zackenberg）长期监测项目（1996-2014年）中通过陷阱诱捕得到的狼蛛（wolf spider）冰川豹蛛（Pardosa glacialis）标本。我们对单个卵囊进行解剖，统计卵与发育中期幼体的数量，并测量雌蛛的头胸甲宽度。当发现产卵量频率分布呈双峰型——这是低纬度地区狼蛛产第二窝卵的典型特征——时，我们根据产卵量将卵囊划分为第一窝卵囊与第二窝卵囊。我们检验了第一窝与第二窝卵囊的捕获日期中位数是否存在差异、产卵量是否与雌蛛体型相关，以及……