Edward Baraniak

Developmental changes in cellular and humoral responses of the burying beetle Nicrophorus vespilloides (Coleoptera, Silphidae).

Necrophagous beetles of the genus Nicrophorus have developed various defence mechanisms that reduce the negative effects of adverse environmental conditions. However, many physiological and ecological aspects, including the functioning of the immune system in burying beetles, are still unknown. In this study, we show developmental changes in cellular and humoral responses of larvae, pupae, and adults of Nicrophorus vespilloides. We assessed changes in total haemocyte count, phenoloxidase activity, and phagocytic ability of haemocytes. We found that during larval development there is a progressive increase in humoral and cellular activities, and these responses are correlated with alterations of total haemocyte counts in the haemolymph. In the pupal stage, a sharp drop in the number of phagocytic haemocytes and an increase in phenoloxidase activity were observed. In adults, cellular and humoral responses remained at a lower level. It is probable that high lytic activity of anal and oral secretions produced by parents supports a lower response of the immune system in the initial phase of larval development. In the studied stages, we also observed differences in polymerisation of F-actin cytoskeleton of haemocytes, number of haemocytes forming filopodia, and filopodia length. These results suggest that the differences in immune responses during various stages of development of N. vespilloides are associated with a dynamically changing environment and different risks of infection. For the first time a detailed analysis of stage-specific alterations in immune system activity during development of the burying beetle is presented.

Appearance and migration of the horse-chestnut leafminer Cameraria ohridella in relation to city size and leaf-raking, using the example of two cities in Western Poland

Possible differences in the size and dynamics of the appearance of particular generations of Cameraria ohridella were studied at two city sites of different size and character. The differences in the degree of infestation of Aesculus hippocastanum by the horse chestnut leafminer in the two towns are interpreted as a result of the differences in the size of food resources. The greater degree of infestation of trees in Mosina relative to trees in Poznań is most probably a result of the difficulty of aerial dispersion and thereby much stronger competition for food. This conclusion confirms a positive correlation of the distance between localities with the degree of tree infestation in a small town and the lack of such a correlation in a big city. The presence of refuges in the city outskirts at which no raking and removal of leaves is performed does not seem to have a significant effect on the degree of horse chestnut infestation in the centre.

Light conditions affect the performance of Yponomeuta evonymellus on its native host Prunus padus and the alien Prunus serotina

The bird cherry ermine moth, Yponomeuta evonymellus L., is considered an obligatory monophagous insect pest that feeds only on native European Prunus padus L. In recent years, however, increased larval feeding on alien P. serotina Ehrh. has been observed. In both species, general defoliation is extensive for shade grown trees, whereas it is high in P. padus, but very low in P. serotina, when trees are grown in full light conditions. The aim of the present study was to identify how the plant host species and light conditions affect the performance of Y. evonymellus. The influence of host species and light condition on their growth and development, characterized by the parameters of pupation, adult eclosion, body mass, potential fecundity, and wing size, was measured in a 2 × 2 experimental design (two light treatments, two hosts). In comparison with high light (HL) conditions, a greater percentage of pupation and a longer period and less dynamic adult emerge was observed under low light (LL) conditions. The effect of host species on these parameters was not significant. In contrast, mass, fecundity and all of the studied wing parameters were higher in larvae that grazed on P. padus than on P. serotina. Similarly the same parameters were also higher on shrubs in HL as compared with those grown under LL conditions. In general, light conditions, rather than plant species, were more often and to a greater extent, responsible for differences in the observed parameters of insect development and potential fecundity.

Larval food affects oviposition preference, female fecundity and offspring survival in Yponomeuta evonymellus

1. Yponomeuta evonymellus is a monophagous moth that feeds on Prunus padus which is native to Europe. In recent years, larval feeding and egg clusters have also been observed on non‐native Prunus serotina plants; however, survival of larvae on this new host is very low.

Impact of cold on the immune system of burying beetle, Nicrophorus vespilloides (Coleoptera: Silphidae).

Insect overwintering is one of the most astonishing phases of the insect life cycle. Despite vast amounts of knowledge available about the physiological mechanisms of this phenomenon, the impact of stress factors on insect immune system functioning during the winter is still unknown. The aim of this study is to analyze how low temperatures influence the immune system of the beetle Nicrophorus vespilloides. The results show that the beetles immune system is differently modulated by cold induced in laboratory settings than that which occurs in natural conditions. Among beetles cultured in conditions similar to summer, low temperatures, did not influence the number of circulating haemocytes, phenoloxidase activity, haemocytes morphology, and percentage ratio of haemocyte types. In these beetles, differences were noted only in the ability of haemocytes to perform phagocytosis. Individuals acclimated in natural conditions in autumn had a higher level of humoral response and a different percentage ratio of haemocyte types. During the winter period, the number of haemocytes in the beetles decreased, but the percentage ratio of phagocytic haemocytes increased. Furthermore, we noted an increase of phenoloxidase activity. Our study also showed mitotic divisions of haemocytes in haemolymph collected from burying beetles after cold exposure and from burying beetles collected from natural conditions during autumn and winter. Differences in response to low temperatures in laboratory conditions and the natural environment suggest that the simultaneous presence of other stress factors during winter such as desiccation and starvation have a significant influence on the activity of burying beetles immune system.

Impact of Cameraria ohridella on Aesculus hippocastanum growth and long-term effects of trunk injection with pesticides

ABSTRACT Defoliation caused annually by Cameraria ohridella has a considerable impact on the general condition of horse chestnut trees. We investigated the consequences of tree endotherapy against this insect. Wood samples, leaves and insect specimens were collected ten years after the treatment (injection) with pesticides. Insect invasion was manifested in all investigated trees by distinct radial growth depression. Treatment resulted in a growth upturn, while non-treated trees maintained decreased growth. The overall foliage infestation level was lower in treated trees, but pupal mass and potential fecundity of insect females were not affected. Our study revealed a long-lasting, positive effect of endotherapy on trees’ appearance and growth.

A new species of Rhigognostis (Lepidoptera, Plutellidae) from the Canary Islands

Rhigognostis canariella sp. nov. is described from the Canary Islands on the basis of five females. The morphological micro structures of the female genitalia are figured. An illustrative diagnostic summary for three allied congeners, R. annulatella(Curtis, 1832), R. kovacsi (Gozmány, 1952) and R. schmaltzella (Zetterstedt, 1839) is provided.

Revised taxonomic status of Eidophasia zukowskyi Amsel, 1938 (Lepidoptera, Plutellidae) with first description of its male and female genitalia

We revise the taxonomic status of Eidophasia zukowskyi Amsel, 1938, and we provide the first descriptions of the genitalia of both sexes. A diagnostic summary is given with illustrations for a similar congener, Eidophasia syenitella (Herrich-Schäffer, [1854]).

Redescription of Eidophasia syenitella (Herrich-Schaffer, [1854]) (Lepidoptera, Plutellidae)

The Holarctic genus Eidophasia Stephens, 1842 belongs to Plutellidae (Kyrki 1984, 1990; Dugdale et al. 1999). The genus currently includes 12 species (Sohn & Baraniak in press) which are heterogeneous in morphologies. In fact, there have been no convincing synapomorphies proposed for Eidophasia. Eidophasia syenitella (Herrich-Schäffer, [1854]) is one of the European congeners. Herrich-Schäffer (1853-1855) associated E. syenitella with E. messingiella (Fisher von Röslerstamm, 1840), based two superficial similarities, i.e. a slim body and the presence of scale tuft on the 2nd segment of the labial palpus. Friese (1966) synonymized E. concinnella Christoph, 1888 and E. zukowskyi Amsel, 1939 under E. syenitella. After examining various local populations of E. syenitella from Europe, we found Frieses synonymy unwarranted. Eidophasia syenitella has been characterized with only its external appearance. There is yet no description of the genitalia available for the species. This gives a challenge in evaluating the taxonomic status of E. syenitella and its two putative synonyms. This issue needs further attention and will be scrutinized in separate papers. Little is known about the biology of E. syenitella. The known larval host records suggest that this species is exclusively associated with a genus of Brassicaceae, Arabis or rockcress. The aim of this paper is to re-describe the species with the genitalia of both sexes for the first time.

Redescription of Argyresthia mirabiella Toll, 1947 (Lepidoptera: Argyresthiidae)

Moths of the family Argyresthiidae are widely distributed globally, as they include a few cosmopolitan species (Dugdale et al. 1999). So far the family has not been the subject of any monograph, and the systematic position of many species is unclear (Agassiz 1996). This applies also to Argyresthia mirabiella (Toll, 1947). Its type specimen with the microscopic slide of the female genitalia is deposited in the collection of S. Toll, at the Institute of Systematics and Animal Evolution, Polish Academy of Sciences (Krakow, Poland). Toll’s (1947) description of this species is limited to a few lines of text. The female genitalia are described in a few sentences concerning the antrum, ductus bursae, and signum. The drawing is schematic and greatly simplified. That brief description of A. mirabiella does not allow its proper identification. Here we provide a more detailed re-description and illustrations based on a re-examination of the type.