• Applied Microscopy
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• v.42 no.1
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• pp.17-26
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• 2012

Histologic and microstructural changes during the postembryonic development of the wolf spider Arctosa kwangreungensis were studied using light and scanning electron microscopy to examine the relationship between a morphological differentiation and behavioral properties. The postembryo with abdominal yolk sac was stayed inactive in the egg case because its muscular and visual systems were not fully developed to a functional level. The first instar spiderlings, developed from the postembryo by a first molting process, started to exhibit its pigmentation on their body cuticles. In particular, undifferentiated cell clusters of central nervous system (CNS) were densely distributed within the cephalothorax, and highly differentiated abdominal ganglion was observed. They had a characteristic visual system looks more like its adult counterpart, and had segmented appendages looks more like the tiny spiders containing well oriented muscular system. After 3rd instar, spiderlings grew more rapidly with accordance to their consistent growth and periodical molting processes. Thus, the relative area of CNS with respect to cephalothorax was gradually decreased, instead a pair of venom glands, musculature, and connectives occupied the residual area. It has been revealed that the early development of spider can be controled by the feeding condition of larval period, since histologic and microstructural differentiations in both appendages and optic system were completed at the second instar. In particular, behavioral properties of the wandering spiders that depend on vision and their running ability were deeply related to physiological differentiation of the microstructural development.

• Korean Journal of Organic Agriculture
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• v.27 no.4
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• pp.463-477
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• 2019

This study was conducted to compare the community structure and biodiversity of epigeic spiders between pear fields cultivated by integrated pest management (IPM) and organic methods. This is the first study of this kind to be conducted in Korea. Eighty-four spider species from 22 families were identified among the collected 2,489 arthropods, with 754 individuals being sampled from IPM fields and 1,735 individuals from organic fields. Generally, Theridiidae, Linyphiidae, Lycosidae, Agelenidae, Gnaphosidae, and Salticidae were the dominant spider families in the pear orchard regardless of the farming methods, and species richness and abundance were higher in organic fields than in IPM fields. The dominant species were the wolf spiders (Lycosidae) and stone spiders (Gnaphosidae), and their cumulative abundance was 70.7% in IPM fields and 72.7% in organic fields. The community structure between organic and IPM fields was heterogeneous, with a 45% similarity level. Biodiversity, species richness, abundance, and species diversity index were higher in organic fields than in IPM fields, and significantly different between the farming methods. Seasonal fluctuations in biodiversity were similar in both IPM and organic fields. The species richness and species diversity index increased and the abundance decreased in the second half of the cultivation period. This study on the community structure and biodiversity of epigeic spiders, which form one of the most important predator groups, will provide principal ecological and faunistic information required to maintain the biodiversity of useful arthropods in agricultural ecosystems and help implement sustainable agriculture based on the active use of natural enemies.

• Journal of Species Research
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• v.8 no.3
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• pp.283-287
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• 2019

Pardosa pseudolaevitarsis n. sp. and Hygrolycosa umidicola Tanaka, 1978 belonging to Lycosidae are described from Korea. To date, fourteen species in the genus Pardosa C. L. Koch, 1847 have been described from Korea. H. umidicola belongs to Hygrolycosa Dahl, 1908 was once described from Korea, but the previous description of this species could not provide adequate scientific evidence for adding H. umidicola to the Korean spider fauna. Pardosa pseudolaevitarsis n. sp. is similar to P. laevitarsis Tanaka & Suwa, 1986 in the shape of its epigyne and palp, but can be distinguished by the followings: epigynal atrium small; spermathecae extending to the end of atrium; shape, location and orientation of fertilization duct in epigyne and internal genitalia; blunt basal spur of median apophysis in palp; number, shape and arrangement cheliceral teeth on both margins. Both species were collected using pitfall traps on a ridge between rice fields and seem to prefer habitats with relatively high humidity.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.331-338
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• 2017

In the present study, we investigated the effects of two herbicide-resistant genetically modified rice (GM rice) varieties, Milyang 204 and Iksan 483, recently developed in Korea on non-target insects and a spider. No difference in host preferences of the English grain aphid Sitobion avenae and the brown planthopper Nilaparvata lugens were observed between GM rice and non-GM rice. Wolf spider Pirata subpiraticus, feeding on N. lugens reared on GM rice or non-GM rice, revealed no significant difference in body weight. P. subpiraticus, fed with N. lugens reared on Milyang 204, showed survival rates similar to that in P. subpiraticus fed with N. lugens reared on non-GM rice. However, P. subpiraticus feeding on N. lugens reared on Iksan 483 demonstrated significantly lower survival rates than that in P. subpiraticus feeding on N. lugens reared on Milyang 204 or non-GM rice. In addition, when larvae of the western honeybee Apis mellifera were supplied with Iksan 483 pollen, a significantly longer pupal period occurred, as compared with that of A. mellifera supplied with pollen of Milyang 204 or non-GM rice. As GM rice has negative effects on P. subpiraticus, which is an important predator in agricultural ecosystems, and on A. mellifera, which plays important roles in pollination and honey production, additional studies on risk assessment of GM rice should be conducted before releasing newly developed herbicide-resistant GM rice to the agricultural environment.