Abstract：
Seasonality considerably impacts on the life of organisms and leads to numerous evolutionary adaptations. Some species face seasonal changes by entering a diapause during different life stages. During adulthood, a diapause in the non-reproductive period can affect male gametogenesis as, for example, it occurs in insects. Spiders are distributed worldwide and show a variety of life cycles. However, data on spiders\' life cycles and seasonal adaptations are limited. Here, we explored the effect of reproductive diapause in a seasonal spider for the first time. We used the South American sand-dwelling spider Allocosa senex as a model as this species is diplochronous, meaning that individuals live two reproductive seasons, with juveniles and adults overwintering in burrows. It has been observed that individuals of this species reduce their metabolism during the non-reproductive season, diminishing prey consumption and locomotion to a minimum. This species is also well-known for exhibiting wandering and courting females and sedentary males. We analyzed spermatogenesis throughout the male\'s life cycle and described the male\'s reproductive system and spermiogenesis using light and transmission electron microscopy. We found that spermatogenesis in A. senex is asynchronous and continuous. However, when males face the non-reproductive season, the late spermatogenic stages and spermatozoa decline, causing an interruption but not a total arrest of this process. This seasonality is also reflected in smaller testes\' size in males from the non-reproductive season than in other periods. The mechanisms and constraints are unknown, but they could be related to the metabolic depression during this life cycle period. Since sex-role reversal apparently sets a low-intensity sperm competition scenario compared with other wolf spiders, surviving two reproductive seasons may balance mating opportunities by distributing them between both periods. Thus, the partial interruption of spermatogenesis during diapause could allow new mating encounters during the second reproductive season.
摘要：
季节性会极大地影响生物体的生命，并导致许多进化适应。一些物种通过在不同的生命阶段进入滞育而面临季节性变化。在成年期,非生殖期的滞育会影响男性配子的发生，例如,它发生在昆虫中。蜘蛛分布在世界各地，并显示出各种生命周期。然而,关于蜘蛛生命周期和季节性适应的数据是有限的。这里,我们首次探索了季节性蜘蛛的生殖滞育效果。我们使用南美沙居蜘蛛Allocosasenex作为模型，因为该物种是双同步的，这意味着个体生活在两个繁殖季节，青少年和成年人在洞穴中越冬。已经观察到，该物种的个体在非生殖季节减少了新陈代谢，将猎物消耗和运动减少到最低限度。该物种也以表现出流浪和求爱的雌性和久坐的雄性而闻名。我们分析了整个男性生命周期中的精子发生，并使用光学和透射电子显微镜描述了男性的生殖系统和精子发生。我们发现A.senex的精子发生是异步和连续的。然而,当雄性面临非生殖季节时，生精后期和精子减少，造成这一过程的中断，但不是完全逮捕。与其他时期相比，非生殖季节的男性睾丸尺寸较小也反映了这种季节性。机制和约束是未知的，但它们可能与生命周期中的代谢抑制有关。由于与其他狼蜘蛛相比，性别角色逆转显然设定了低强度的精子竞争场景，生存两个繁殖季节可以通过在两个时期之间分配它们来平衡交配机会。因此，滞育期间精子发生的部分中断可能会在第二个生殖季节进行新的交配。
