Pardosa pseudoannulata, a member of a group of species referred to as wolf-spiders, is a non-web-building spider belonging to the family Lycosidae. P. pseudoannulata are wandering spiders that track and ambush prey and display sexual cannibalism. They are commonly encountered in farmlands across China and other East Asian countries. Their venom has properties that helps it function as an effective insecticide, and it is, therefore, a crucial pesticide control agent.
Description
Pardosa pseudoannulata exhibits significant sexual dimorphism in terms of size. Females are, on average, 1.3 times larger than the males. This spider can be recognized by the ring markings on its legs and the dark bands on its carapace. The underside of these spiders is characterized by six black dots. Female P. pseudoannulata are easy to detect, as most will have an egg sac attached to their spinnerets. P. pseudoannulata have three rows of eyes with the front row having four eyes and the other rows having two eyes each.
Habitat and distribution
Distribution
Pardosa pseudoannulata is widely spread across China, India, Korea, Japan and other countries in East Asia. It is most commonly found in farm fields throughout China. These spiders are commonly seen in rice fields and are the dominant predator.
Habitat
Pardosa pseudoannulata commonly inhabits arable farm fields and similar open habitats. It is one of the most common surface-dwelling spider species in Central China and plays an important role as a control agent against pests and insects within the crop fields. The spider is also found near fields with ponds and has the ability to move swiftly over bodies of water. Due to the nature of agriculture, the fields will remain fallow for several months, decreasing the density of prey that migrate into the field to take advantage of nutrients in the crops. This causes P. pseudoannulata to starve for multiple months at times, explaining why they are well adapted to survive in environments with insufficient resources.
In order to produce the maximum number of eggs and the highest rate of successful hatchings, Pardosa pseudoannulata prefers temperatures between 20 and 30 oC, the optimal temperature being 25 oC. If the temperature is lower than 10 oC, the spiders will stop eating and, as a result, will not grow or develop. In temperatures above 40 oC, the spiders will move slowly and remain hidden in burrows.
Diet
Pardosa pseudoannulata commonly starve and have a hard time foraging for sufficient nutrients. Therefore, the occurrence of sexual cannibalism provides an adaptive strategy for female survival as well as reproductive benefits. Pre-copulation cannibalism in which the male spider is used solely as food is commonly observed in females who have already mated. The consumption of conspecifics makes up a quarter of the female's diet. Male spiders are an especially good source of nutrition because of their large size (females are 1.3 times larger) when compared to natural prey, which are insects that are several times smaller than the females.
The natural prey of Pardosa pseudoannulata are rice field pests, with the rice brown planthopper, Nilaparvata lugens, as the most common. N. lugens are abundant in rice fields and detrimental to the growth of rice plants. Pardosa pseudoannulata prefers the rice brown planthopper over other pests, with the planthopper making up around 30% percent of an average spider's diet.
Abdomen size
Pardosa pseudoannulata’s abdomen width is an important indicator of its hunting abilities and starvation resistance. There is a trade-off between the hunting abilities and the period of time the spider can withstand hunger. Spiders with larger abdomens are seen to withstand starvation for longer periods of time, whereas spiders with smaller abdomens are seen to be better and more agile hunters.