Reproductive biology of agrobiont linyphiid spiders in relation to habitat, season and biocontrol potential

Linyphiid spiders are generalist predators, which have potential to prevent pest outbreaks provided they are present in high numbers early in the pests’ population growth. Crop management reduces spider populations several times a year. Reproduction is therefore important for recovery of the generalist population. This study aimed to compare the reproductive biology of common agrobiont linyphiids (i.e., dominant species in agroecosystems). Linyphiid females were collected over 4 years from winter wheat, pasture, and set-aside (arable land where cultivation is abandoned) in Denmark and UK. The eggsacs they produced were incubated under field conditions. Clutch size (eggs per eggsac) and eggsac production rate (eggs per female per week) varied among species and seasons. An interspecific comparison showed a trade-off between reproductive rate and clutch size, which indicated that the species adapt different life history strategies of reproductive allocation. We found only minor differences in clutch size and eggsac production rate among agricultural habitats. Most of the species studied begin reproduction early in the year and continue through the growing season making them good candidates for natural biological control.