- An unidentified harvestman Leiobunum sp. alarmingly invading Europe (Arachnida: Opiliones) (2007)
- Since about the year 2000 a hitherto unidentified species of the genus Leiobunum C. L. Koch, 1839, has rapidly invaded central and western Europe. Records are known from The Netherlands (probably the country of first occurrence in Europe), Germany, Austria and Switzerland. This introduced species, until now, mainly inhabits walls of buildings and rocky environments. Adults characteristically aggregate during daytime into groups of up to 1.000 individuals. The species is described and details on its present distribution, habitat preference, phenology and behaviour are presented.
- Sensory structures and sexual dimorphism in the harvestman Dicranopalpus ramosus (Arachnida: Opiliones) (2013)
- A survey on sensory organs of both sexes of the harvestman Dicranopalpus ramosus classifies structure and frequency of campaniform sensilla, falciform setae, sensilla basiconica, slit sensilla, solenidia, spines, sensilla chaetica, trichomes (simple hairs) and plumose setae. Sensilla are equally distributed on the pedipalp tarsi of both males and females, but females show higher counts of campaniform and falciform setae than males. Females furthermore have about 1000 glandular plumose setae on each pedipalp, that at the same positions in males are replaced by sensilla chaetica. The walking legs of both sexes show a similar distribution of sensory organs, with females showing more sensilla basiconica at the legs I and II and more solenidia on the first pair of legs. Males have a large number of bipterate setae (about 2200 per specimen) at the metatarsi and tarsi of the third and fourth pair of legs. In females these are replaced by simple hairs. Although females show a similar (or slightly higher) number of leg sensilla than males, their density is higher due to their shorter legs. In both sexes the second pair of legs has the largest number of falciform setae, sensilla basiconica, chaetica and solenidia, followed by the legs I, III and IV. The first pair of legs has the highest density of falciform setae, sensilla basiconica and solenidia, followed by the legs II, III and IV. The genital operculum, sternites and tergites show a multitude of slit sensilla. The slit sensilla of the genital operculum and sternites are associated with insertion plaques of muscles operating the penis/ovipositor and regulating opisthosomal volume and hemolymph-pressure.
- Notes on the biology of the unidentified invasive harvestman Leiobunum sp. (Arachnida: Opiliones) (2011)
- Since about the year 2000 an unidentified, introduced harvestman of the genus Leiobunum has been rapidly invading Europe. The published records are from the Netherlands, Germany, Austria and Switzerland. A population of Leiobunum sp. in the Netherlands was studied frequently during the day and night. Its life cycle, hunting strategy, diet and accompanying harvestman species were recorded, and mating, male-male fights and ovipositing behaviour studied, as well as the spider species preying on this Leiobunum species. Food items were collected, indicating that its food consists of a wide range of live as well as dead invertebrates including spent spider prey scavenged for at ground level. Vegetable matter like berries, as well as bird droppings were also consumed. The mating strategy is very complex. A male guards an egg depositing female and he defends her against other advancing males, resulting in male-male fights. The guarding male frequently mates. Also courtship behaviour has been observed, including nuptial feeding with a fluid, probably originating from the accessory penal glands and delivered by the male into the female’s stomotheca via sacs located on the distal part of the penis truncus. Eggs are deposited in holes and crevices of walls.