Differentiation of flea communities infesting small mammals across selected habitats of the Baltic coast, central lowlands, and southern mountains of Poland

Proteins from shrews' venom glands play a role in gland functioning and venom production

Venom production has evolved independently many times in the animal kingdom, although it is rare among mammals. Venomous shrews produce venom in their submandibular salivary glands and use it for food acquisition. Only a few toxins have been identified in shrew venoms thus far, and their modes of action require investigation. The biological and molecular processes relating to venom production and gland functioning also remain unknown. To address this gap, we investigated protein content in extracts from venom glands of two shrew species, Neomys fodiens and Sorex araneus, and interpreted their biological functions. Applying a proteomic approach coupled with Gene Ontology enrichment analysis, we identified 313 and 187 putative proteins in venom glands of N. fodiens and S. araneus, respectively. A search of the UniProt database revealed that most of the proteins found in both shrew species were involved in metabolic processes and stress response, while GO enrichment analysis revealed more stress-related proteins in the glands of S. araneus. Molecules that regulate molecule synthesis, cell cycles, and cell divisions are necessary to enable venom regeneration and ensure its effectiveness in predation and food hoarding. The presence of proteins involved in stress response may be the result of shrews' high metabolic rate and the costs of venom replenishment. Some proteins are likely to promote toxin spreading during envenomation and, due to their proteolytic action, reinforce venom toxicity. Finally, finding numerous proteins involved in immune response suggests a potential role of shrew venom gland secretions in protection against pathogens. These findings open up new perspectives for studying biological functions of molecules from shrew venom glands and extend our knowledge on the functioning of eulipotyphlan venom systems. Because the majority of existing and putative venomous mammals use oral venom systems to inject venom into target species, the methods presented here provide a promising avenue for confirming or discovering new taxa of venomous mammals.

Parasitic Arthropods of Soricinae Shrews in North-Eastern Poland

The study of the ectoparasite fauna of the insectivores-Sorex araneus, Sorex minutus, Neomys fodiens, and Neomys anomalus (subfamily Soricinae)-was carried out in three locations in Poland: Białowieża National Park, Kosewo Górne in the Masurian Lake District, and in vicinity of Warsaw. Three species of Ixodidae ticks, eleven species of fleas, and four species of mites from the order Mesostigmata were noted. The most numerous ectoparasites are ticks Ixodes ricinus (larvae), Dermacentor reticulatus (nymphs), and fleas Palaeopsylla soricis, Megabothris walkeri, and Hystrichopsylla orientalis. These species show the highest prevalence and show the highest dominance index. The parasitofauna of S. araneus is much richer in species than other shrew species. The structure and dominance of parasite assemblages differ between locations.

Communities of ectoparasitic arthropods associated with the root vole Microtus oeconomus in north-eastern Poland

Ectoparasitic arthropods communities associated with root voles Microtus oeconomus (Pallas, 1776) were analysed in north-eastern Poland. The first M. oeconomus parasites recorded in the history were the fleas Palaeopsylla similis Dampf, Ctenophthalmus congerer Rothschild, C. bisoctodentatus Kolenati, and C. solutus Jordan et Rothschild. Ctenophthalmus uncinatus (Wagner) and Doratopsylla dasycnema (Rothschild) fleas and the Ixodes apronophorus Schulze tick were recorded on M. oeconomus in Poland for the first time. These species are relatively rare in Poland and specific to other species of small mammals. The incidence of M. oeconomus infestations with I. apronophorus, D. dasycnema and C. uncinatus ranged from 0.5 to 0.8 %, respectively. There are large differences in the infestation of Dermacentor reticulatus larvae and nymphs between July and August. In July, D. reticulatus may be considered the dominant ectoparasite species, in August, it is partly replaced by I. ricinus and fleas and is subdominant.

Flea Communities on Small Rodents in Eastern Poland

Fleas are hematophagous insects infesting mainly small mammals and, less frequently, birds. With their wide range of potential hosts, fleas play a significant role in the circulation of pathogens in nature. Depending on the species, they can be vectors for viruses, bacteria, rickettsiae, and protozoa and a host for some larval forms of tapeworm species. The aim of this study was to determine the species composition of fleas and their small rodent host preferences in eastern Poland. Animals were captured in traps in various types of ecological habitats (a site covered by grassland vegetation within city limits, an unused agricultural meadow, and a fallow land near a mixed forest). The following rodent species were caught: Apodemus agrarius, Apodemus flavicollis, Microtus arvalis, and Myodesglareolus. Additionally, Ctenophthalmus agyrtes, Ctenophthalmus assimilis, Hystrichopsylla talpae, and Nosopsyllus fasciatus flea species were identified. The peak of the flea activity was noted in summer months. C. agyrtes was found to be the most abundant flea species in eastern Poland, while the greatest numbers of fleas were collected from the rodent species A. agrarius.

Differences in the ectoparasite fauna between micromammals captured in natural and adjacent residential areas are better explained by sex and season than by type of habitat

We compared the ectoparasite fauna in 608 micromammals (chiefly 472 wood mice Apodemus sylvaticus, 63 Algerian mice Mus spretus, and 51 greater white-toothed shrews Crocidura russula) captured in natural and adjacent residential areas in spring and autumn during three consecutive years in four areas in periurban Barcelona (NE Spain). We found little support for an association of urbanization with differences in infestation by ectoparasites. Prevalence of Rhipicephalus sp. tick in wood mice and shrews was significantly higher in residential than in natural habitats, and the opposite was found for the flea Ctenophtalmus andorrensis catalanensis in shrews. Marked differences in the prevalence of the flea Leptopsylla taschenbergi amitina in wood mice between seasons were observed in natural but not in residential habitats, probably due to enhanced flea survival probabilities in the latter. However, as a rule, males were more frequently and heavily infested than females, and the prevalence was higher in autumn than in spring. Our results suggest that the ectoparasite fauna of periurban micromammals is shaped more by other factors than by habitat modification. People living in residential areas are at risk of contact with the arthropods borne by non-commensal micromammals and the pathogens transmitted by them.

Sex differences in flea infections among rodent hosts: is there a male bias?

Recognizing patterns of parasite distribution among wildlife hosts is of major importance due to growing risk of transmission of zoonotic diseases to humans. Thus, sex-dependent parasite distribution in higher vertebrates is extensively studied, and males are often found more parasitized than females. Male-biased parasitism may be the result of weaker immunocompetence of male hosts owing to the immunosuppressive effect of androgens. Moreover, larger hosts (males) may demonstrate higher parasite infestation levels than smaller individuals (females), as they constitute a better nutritional resource for parasites and provide them with a greater variety of niches. In the present work, we investigated sex-dependent patterns of flea distribution among three common rodent species (Apodemus agrarius, Apodemus flavicollis, and Myodes glareolus). We hypothesized that males have a higher flea infestation than females. We confirm male-biased parasitism in A. agrarius and M. glareolus, but not in A. flavicollis. Additionally, flea infestation increased with body mass in A. agrarius, but not in A. flavicollis and M. glareolus. The detected differences in parasite distribution among sexes are probably the result of immunosuppressive effects of androgens and spatial behavior of males.