We found that the koinobiont ectoparasitoid wasp Zatypota picticollis is exclusively associated with three orb weaving spiders Cyclosa conica, Mangora acalypha and Zilla diodia from the family Araneidae. Under the influence of the parasitoid's final instar larva the spiders built a specific web architecture, which differed considerably from the capturing orb web. Manipulated webs of C. conica and M. acalypha lacked the spiral, stabilimentum and central hub, and the radials were reduced in number. The manipulated web of Z. diodia consisted of one strong horizontally oriented thread.

Background: The polysphinctine wasp, Acrodactyla quadrisculpta, is a koinobiont ecto-parasitoid of spiders and is narrowly associated with the biology of its spider hosts. The larva, attached to the dorsal side of the abdomen, develops while the spider continues foraging. Shortly before pupation, the parasitoid larva manipulates the web-building activity of the host in order to construct a safe shelter against natural elements and predators during parasitoid pupation.

Climate change could promote the altitudinal spread of C4 weed species since they can benefit from warmer climate. The effects of altitude and climatic conditions (the sum of temperatures above 5°C and precipitation) on the biomass and seed production of two annual C4 weeds -Amaranthus retroflexus L. and Echinochloa crus-galli (L.) P. Beauv. -were studied in the Czech Republic. We included both temperature and precipitation variables in the study since they both serve as basic indicators of climate change and thus they have the greatest impact on plant development. The experiment was carried out by sowing both weed species on m 2 area with four replicates in seven localities differing in altitude in 2010 and 2011. We found no significant impacts due to altitude on any variables measured. However, climatic factors explained 44.5% of the variation in plant dry biomass and 41.4% of the seed number produced by A. retroflexus. The same variables did not significantly contribute to the variation in aboveground biomass or seed number of E. crus-galli. These results show the impact of climate conditions to vary between species and not to limit reproduction at high altitudes.

The life history of polysphinctine parasitoids is poorly understood. As a result, their effect on their host has not been evaluated. Here, we present the phenology of Zatypota percontatoria, an ectoparasitoid wasp of theridiid spiders, using rich field, semi-field and laboratory investigations of selected life-history parameters. The wasps overwintered as larva attached to the spider abdomen and the imagos of the first generation emerged at the beginning of May. The sex ratio (F/M) of overwintered wasp larvae was 1.4. The wasp spent an average of 6.4 days in the egg stage, 27.67 days in the larval stage and 9.6 days in the pupal stage. Adult longevity was on average 14.34 days. Oviposition occurred on average 8.44 days following maturity. The wasp laid on average 0.35 eggs/day. The total fecundity was on average 7.4 eggs per wasp and decreased with age (data from unmated females). The developmental rate increased with experimental temperature up to 28°C. The lower developmental threshold for pupae was estimated at 6.6°C. The sum of effective temperatures for pupae was estimated at 157.8 degree days. Using daily temperature records from the Czech Republic over the last 41 years, we estimated an average of 3.5 generations of Z. percontatoria per year. Mortality was 48% in semi-field conditions and 23% in the laboratory. The incidence of mortality was highest during egg and larval stages caused by the detachment of eggs or larvae during spider molting, the mortality of the spider-host and egg deposition on the spider prosoma.