• Journal of Ecology and Environment
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• 제32권1호
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• pp.33-39
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• 2009

Brood caring behavior was observed in Amaurobius ferox (Araneae, Amaurobiidae), a semelparous subsocial spider, from cocoon construction until the emergence of spiderlings from the cocoon. Unlike most spiders, which emerge from cocoon by their own means, A. ferox mothers intervene in the process of the emergence of their young. I manipulated broods by removing the mother prior to emergence to determine the effects of maternal behavior on the emergence of spiderlings. My results showed that maternal intervention making the cocoon expansion and its exit, is not absolutely necessary for the emergence of A. ferox spiderlings from the cocoon. Nine clutches out of ten were able to get out of the cocoon by their own means without their mother's help. There was no difference between control groups ('with mother') and experimental groups ('without mother') in the number of spiderlings that emerged ($96.9{\pm}25.3$ vs. $90.4{\pm}14.2$, respectfully) and in the time from the beginning to the end of emergence ($36{\pm}12$ vs. $41{\pm}17$ hours). Time from eclosion until the emergence of the first individual in a clutch, however, was greater in the mother-absent group (3.5 days) than in the control group (2.0 days). The construction of the cocoon by the mother required always occurred in the same area within the retreat, and took approximately 6 hours, and the mother guarded the eggs during the incubation period. The emergence of the spiderlings followed a sigmoidal pattern. After emergence, the spiderlings formed a very compact group on the cocoon, which may be important in securing maternal care. The absence of cribellum and calamistrum, structures likely involved in their survival, observed in individuals of the first instar suggests that in the first stage of life, the spiderlings are dependent on their mother.

• Journal of Ecology and Environment
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• 제32권3호
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• pp.177-182
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• 2009

The optimal strategy for semelparous females may involve adjustments in the relative investment in two fitness components, the number of offspring and the post-hatching investment per capita. To determine the pattern of maternal resource allocation to offspring in the matriphagous spider, Amaurobius ferox (Amaurobiidae), I investigated the relationship between maternal body-mass and the number of offspring, and quantified the transfer of maternal body-mass to the offspring via different forms of maternal provisioning (trophic egg-laying and matriphagy). There was a positive relationship between female body-mass and the number of offspring. However, Amaurobius mothers did not produce more trophic eggs when they had larger broods. Rather, spiderlings in larger A. ferox broods consumed larger quantities of maternal body-mass via matriphagy. Mothers transferred $28.8{\pm}6.5%$ of their body-mass to the spiderlings via trophic egg-laying, and an estimated $39.0{\pm}12.5%$ of their body-mass was transferred to the spiderlings via matriphagy.

• Animal cells and systems
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• 제3권2호
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• pp.167-172
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• 1999

We report for the first time the life history of a 'social' spider, Philoponella prominens, living in a temperate region. Philoponella prominens hibernated as immatures or subadults for 7-8 months in 1995 and 1996 from September-October to April-May in central Korea. When they emerged from their winter hibernation, a majority began their lives as commensals in the webs of other species. As the mating season approached, however, commensal spiders switched to become colonial or solitary. The mating season began in early June and lasted until early August. Newly-hatched spiderlings began to appear in the field in late June. They formed a colony by building their webs connected to the mother's by using pan of the mother's web as supporting substrates. As the season progressed, however, some of the colonial spiderlings became commensal or solitary individuals. Our field observations suggest that Philoponella prominens form colonies or commensal associations to reduce the web-building cost.

• Journal of Ecology and Environment
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• 제30권4호
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• pp.315-318
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• 2007

Cooperative or non-territorial permanently social spiders are believed to have evolved from species showing subsocial maternal care. The transition from subsocial to cooperative social groups probably involved a transition from an outbreeding breeding system to one with inbreeding. Nepotistic recognition among siblings should facilitate the evolution of social cooperation through avoidance of inbreeding and maintenance of mutual tolerance between siblings. We conducted experiments to determine whether a mechanism for sibling recognition is present in the subsocial spider, Coelotes terrestris which displays extended maternal care in the form of food provisioning. The numbers of surviving individuals within unfed groups were observed and compared between non-sibling groups of ten spiderlings and groups of ten siblings. The number of survivors differed significantly between groups, with consistently fewer spiderlings surviving in the non-sibling groups than the sibling groups over the study period. This result suggests that sibling recognition and nepotism do occur in this subsocial species. The nepotism involved in the maternal social organization of the Coelotes might be an example of a preadaptation facilitating the evolution of permanent social life.

• Applied Microscopy
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• 제42권1호
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• pp.17-26
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• 2012

배회성거미류의 배후발생과정에서 형태적 분화가 행동학적 특성으로 발현되는 기전을 규명하기 위하여 광릉늑대거미(Arctosa kwangreungensis) 후기배아와 각 발생 단계의 유충을 실험재료로 그 조직학적 및 미세구조적 변화를 광학 및 주사전자현미경으로 분석하였다. 난황주머니를 가진 후기배아는 부속지의 근육조직과 신경절의 미분화로 비활성상태를 유지하며, 시각기의 신경절과 신경의 발달도 미약하였다. 제1령 유충의 두흉부에서는 미분화된 세포집단이 관찰되고 체색의 발현과 복부신경절의 분화가 현저하였다. 먹이 활동을 시작하는 제2령 유충의 중추신경계에는 신경섬유가 급격히 증가되었고, 성체와 유사한 부속지의 분절구조와 시각기의 조직학적 체제가 확립되었다. 제3령 이후의 유충들은 탈피를 거듭하여 두흉부에서 중추신경계가 차지하는 영역이 축소되었고 독선과 근육조직, 그리고 결합조직등의 활발한 분화가 진행되었다. 먹이활동을 시작하는 제2령 유충 단계에서 부속지와 시각기의 조직학적 발생과 이를 통제하는 신경계의 분화가 완료되는 것으로 미루어, 섭식환경이 배후발생과정을 조절할 수 있으며, 특히 시각과 부속지에 의존하여 먹이를 포획하는 배회성거미류의 행동 습성이 형태조직학적 분화와 연관되어 있음을 확인할 수 있었다.

• Journal of Ecology and Environment
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• 제32권3호
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• pp.145-148
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• 2009

To understand whether experience of cold season in reproductive behaviors in the adults of Amaurobius ferox, the paired adults of a female and a male were exposed under 'cold-treated environment' and 'not cold-treated environment', respectively. I investigated effects of the cold treatment on the brood production of A. ferox. In not cold treatment in which male-female pairs were formed in October at a temperature of $20^{\circ}C$ (${\pm}2^{\circ}C$) and continuously kept under not cold-treated environment, only 3 of 50 pairs successfully reproduced (reproduction was defined as the emergence of spiderlings). In cold treatment where individuals were kept in cold conditions for 3 months prior to pair formation, 57 out of 60 couples succeeded in reproducing. Females which did not experience the low temperature displayed strong aggressiveness toward males. This behavioral inhibition might the primary barrier to copulation of A. ferox that decrease following a period of low temperature. The reproductive inhibition might help the females to allocate the maximum amount of energy in a given environment to reaching the adult stage and to delay reproduction in unfavorable wintering conditions.

• Applied Microscopy
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• 제38권2호
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• pp.89-96
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• 2008

배회성거미류의 일종으로 주로 물가에 서식하는 닷거미과 (Pisauridae)의 황닷거미(Dolomedes sulfureus)를 실험재료로 실크 분비장치의 미세구조를 주사전자현미경(FESEM)으로 관찰하고, 토사관의 미세구조적 특성을 분석하였다. 황닷거미는 먹이를 포획하기 위한 거미줄을 만들지 않지만, 유충을 보호하기 위한 그물을 만드는 종류로 병상선(ampullate glands), 이상선(pyriform glands), 포도상선(aciniform glands) 등, 세 종류의 견사선과 이와 연결된 실젖 표면의 독특한 토사관을 가지고 있었다. 두 쌍의 대 병상선은 앞실젖을 통해, 그리고 또 다른 두 쌍(수컷의 경우 1${\sim}$2쌍)의 소병상선은 가운데실젖을 통해 분비관이 연결되어 있었다. 이상선은 앞실젖 표면의 토사관을 통해(암컷: 62${\sim}$68쌍, 수컷: 45${\sim}$50쌍) 분비되었고, 포도상선은 가운데실젖(암컷: 33${\sim}$40쌍, 수컷:18${\sim}$25쌍)과 뒷실젖(암컷: 42${\sim}$50쌍, 수컷: 24${\sim}$28쌍)의 토사관을 통해 분비됨이 확인되었다. 이들 중, 병상선과 연결된 토사관이 암수 모두에서 가장 현저한 분비 특성을 가진 것으로 관찰되었다.