Masaki Sinzo
Laboratory of Entomology, Faculty of Agriculture, Hirosaki University, 036, Hirosaki, Aomori, Japan.
Oecologia. 1979 Nov;43(2):207-219. doi: 10.1007/BF00344771.
The cricket tentatively identified as Pteronemobius taprobanensis shows a stepwise pattern of latitudinal variation in ovipositor length. Abrupt elongation of ovipositor at about 28° N marks the replacement of the subtropical form by the temperate form. The latter maintains almost a constant ovipositor length up to about 35° N within the bivoltine area. Further north in the univoltine area, an ascending cline extends to about 39° N, beyond which no further increase occurs. The ovipositor length adjusted for body size shows a northeastward increase in each of the univoltine and bivoltine areas, though this tendency is less clear in the latter. The optimum length of ovipositor would vary with the relative amounts of gain (due to the protection of eggs in the soil) and loss (due to the metabolic cost and the difficulty to emerge from the soil) in fitness. If so, it may be predicted that a longer ovipositor would be selected for, when the metabolic cost and the risk at hatching are smaller, the environmental pressure in the egg stage is stronger, and the egg stage lasts longer. The last parameter seems to be mainly responsible for the observed association of the type of life cycle with the geographic pattern of variation in ovipositor length.
初步鉴定为塔普罗斑蟋的蟋蟀，其产卵器长度呈现出纬度变化的阶梯式模式。在北纬约28°处产卵器突然伸长，标志着亚热带形态被温带形态所取代。在二化性区域内，后者在北纬约35°以北保持着几乎恒定的产卵器长度。在更北的一化性区域，一个上升的梯度延伸到约北纬39°，超过该纬度后不再增加。根据体型调整后的产卵器长度在一化性和二化性区域均呈现出向东北方向增加的趋势，尽管在后者中这种趋势不太明显。产卵器的最佳长度会随着适合度方面的相对收益（由于土壤中卵的保护）和损失（由于代谢成本和从土壤中羽化的难度）而变化。如果是这样，可以预测，当代谢成本和孵化风险较小、卵期的环境压力较强且卵期持续时间较长时，会选择更长的产卵器。最后一个参数似乎主要解释了所观察到的生命周期类型与产卵器长度地理变化模式之间的关联。
