The new ectoparasitic dinoflagellate, Oodinium vostokense sp. nov. Savelieva, infecting the appendicularian Fritillaria borealis has been described, for the first time, from the Russian waters of the Sea of Japan. Trophonts of O. vostokense sp. nov. are most similar to those of Oodinium fritillaria Chatton, 1912, parasitising fritillariids (Fritillaria pellucida) from the Mediterranean Sea, in both their general morphology and hosts. The differences consist in the host specificity, the number of trophonts per host, the site of attachment to the host, and several ultrastructural features. As the examination has shown, the infected F. borealis specimens bear one to five trophonts of O. vostokense sp. nov. (five specimens with one trophont each, one specimen with two trophonts, and one specimen with five trophonts). The balloon-shaped trophonts of O. vostokense sp. nov. are attached to different sites on the epidermis of the trunk, including the gonad epidermis, and the epidermis of the tail of F. borealis. The dinokaryotic spherical nucleus of the trophont is located in the upper half of the cytoplasm. The cortical cytoplasm contains large lipid droplets. The adhesive disc is external, with two zones: cortex and medulla. The peduncle stalk is completely intracytoplasmic. The peduncular bulb is constricted centrally by an osmiophilic ring. The pusule is also constricted by an osmiophilic ring and opens outside through a pore represented by a long canal.

Predation can regulate populations and strongly affect invasion success of novel prey. The deer ked (Lipoptena cervi; Linnaeus 1758) is an invasive ectoparasite of cervids that spends a long period of its life cycle outside the host. Prior to this study, virtually nothing was known about natural summer time predation on the deer ked. We aimed to evaluate the magnitude of summer time predation on L. cervi pupae in different habitats and to identify potential predators. We conducted a set of field experiments, where we exposed L. cervi pupae to various ground-dwelling vertebrate and invertebrate predators. The loss of pupae was monitored for different predator guilds. Three habitats of the moose, the main host species, were studied: (1) moist heath forest; (2) dry, logged heath forest; and (3) moist meadow. The results indicate notable summer time predation on L. cervi pupae, and the pupal predation varied within and between habitats, being lowest in the meadow habitat. We found a positive correlation between pupal loss and abundance of the common lizard (Zootoca vivipara), harvestmen (Opiliones), ground spiders (Gnaphosidae) and Formicinae-ants. We conclude that summer time predation during the pupal phase can have a notable local importance for the L. cervi abundance.

Avian hosts may either resist the negative effects of nestling ectoparasites by minimizing the number of parasites, or tolerate parasitism by increasing their fecundity via the reproductive compensation hypothesis. Little is known about the interactions between ectoparasites and their avian hosts in the tropics. We (1) examined nestling development rates, and tested whether (2) parasitism by a subcutaneous ectoparasitic botfly (Philornis sp.) had negative effects on the condition of nestlings, and (3) these negative effects were minimized in larger broods in a tropical cavity-nesting bird, the planalto woodcreeper (Dendrocolaptes platyrostris), in primary and secondary Atlantic forests in the northern province of Misiones, Argentina. Nestling mass and ectoparasite load per nestling reached maxima when nestlings (n = 50) were between 10 and 14 d old. General linear mixed models predicted that mass at fledging declined with increasing nestling parasite load, suggesting that botflies had a negative influence on fledging condition. Parasite load per nestling declined with increasing brood size indicating that woodcreepers that increase their reproductive output minimize the negative effects of parasitism. Overall we found evidence to support the tolerance via reproductive compensation hypothesis. Future tests of the reproductive compensation hypothesis may help determine the underlying mechanism of the observed negative correlation between parasite load of nestlings and brood size.

Nycteribiids (Diptera: Nycteribiidae) are specific haematophagous ectoparasites of bats, which spend nearly all their adult lives on hosts. However, females have to leave bats to deposit their larva on the walls of the roosts, where they later emerge as adult flies. Nycteribiids had thus to evolve efficient sensorial mechanisms to locate hosts from a distance. We studied the sensory cues involved in this process, experimentally testing the role of specific host odours, and general cues such as carbon dioxide, body heat, and vibrations. As models we used two nycteribiids (Penicillidia conspicua and Penicillidia dufourii) and their primary bat hosts (Miniopterus schreibersii and Myotis myotis, respectively). Carbon dioxide was the most effective cue activating and orientating the responses of nycteribiids, followed by body heat and body odours. They also responded to vibration, but did not orientate to its source. In addition, sensory cues combined (carbon dioxide and body heat) were more effective in orientating nycteribiids than either cue delivered alone. Results suggest that nycteribids have some capacity to distinguish specific hosts from a distance, probably through their specific body odours. However, the strong reliance of nycteribiids on cues combined indicates that they follow these to orientate to nearby multispecies bat clusters, where the chances of finding their primary hosts are high. The combination of sensory cues seems therefore an effective strategy used by nycteribiids to locate bat hosts at a distance.

Investigations were carried out on the seasonal population fluctuations of the moth Cydia ptychora. The population increased from May to September and declined from November to April. Increasing temperatures and decreasing r.h. appeared to be associated with population decline, while the reverse seemed to favour population increase.

From light trap catches, sex ratios of adults showed considerable variation from month to month. The overall ratio was 2:1, in favour of the males, but there was a tendency for adjustment towards an apparently female-biased ratio from March to August.

Bracon (?) hancocki was found to be a major parasite. Other biotic factors contributing to population regulation included 13 hymenopterous parasites and three predators (Philodicus temerarius, Bactria sp. nr. guineensis and Chrysopa sp.)