Nematodes Follow a Leader

Aggregated movement and population structure are known in entomopathogenic nematodes, which are obligate insect parasites. Aggregation behavior in the absence of external stimuli suggests communication among individuals, often in the form of trail-following, which has not been shown by nematodes of any kind. Interactions among individuals are an essential basis of following behaviors and can have significant fitness consequences. We explored intraspecific and interspecific interactions among three Steinernema species (S. glaseri, S. carpocapsae, and S. feltiae) in terms of trail following, and fitness outcomes of following heterospecific individuals. We found that the following behavior is context dependent. Following behavior among conspecifics was significantly increased when the lead nematode had prior contact with host cuticle. However, we did not find a clear association between the following response to heterospecific IJs and their reproductive success in a co-infected host.

Entomological images in Karelian beliefs

Introduction. Insects act as an element of the mythological system and rituals, provided by a variety of functions, occupied a certain place in the rituals, beliefs and medical practice of the Karelians. Among domestic insect parasites, the lice are most widely represented in the Karelian language and rituals. The research novelty of the study is determined by the fact that researchers did not turn to the question of the functioning of insects in mythological views and the ritual tradition of Karelians. However, such research is necessary in order to recreate the integrity of the mythological picture of the Karelians, which determines the relevance of this article. Materials and Methods. The material for the study was entomological images in the beliefs and folk medicine of the Karelians. They were considered using comparative historical, comparative and comparative and ethnolinguistic methods. Results and Discussion. The authors dwell on the mythological views of Karelians about domestic parasite insects using the example of lice. These beliefs are reflected in the causes of diseases, methods of treatment, as well as in mythological stories and folklore. Conclusion. The collected and analyzed linguistic and ethnographic data make it possible to come to the conclusion that the lice are the representatives of the entomofauna. Karelians have many beliefs connected with lice, which are reflected in the linguistic picture of the world and traditional culture.

First record of a mermithid worm (Nematoda, Mermithidae) parasitizing a third instar nymph of Triatoma sordida (Stål, 1859) (Hemiptera, Reduviidae, Triatominae) from Mato Grosso, Brazil

A juvenile specimen of a mermithid (Nematoda) was found parasitizing a third instar nymph of Triatoma sordida from Mato Grosso, Brazil. This is the first record of mermithid parasitism in a triatomine species. The Mermithidae represents a family of nematodes that are specialized insect parasites. Entomonematodes are one of the highly influential agents regulating the population dynamics of insects. This report introduces the opportunity to think about mermithids as a possible candidate for use as triatomine biological control.

Insect parasites inhabiting Passer domesticus (linnaeus, 1758) and P. Montanus (linnaeus, 1758) (aves: passeriformes) nests in Voronezh

In Voronezh, 14 species of parasitic insects were found in sparrows and their nests during 2017–2020. It was found 6 species of chewing lice: Menacanthus eurysternus Giebel, 1874, Ricinus fringillae De Geer, 1778, Sturnidoecus ruficeps Giebel, 1866, Brueelia subtilis Giebel, 1874, B. borini Lunkaschu, 1970, and Philopterus montani Zlotorzycka, 1964. Among them, Menacanthus eurysternus was the dominant species for the House Sparrow (dominance 21.70 %, prevalence 10.00) while B. subtilis (dominance 18.60 %, prevalence 8.00) and B. borini (dominance 16.29 %, prevalence 6.00) were subdominant. For the European Tree Sparrow, the dominant species were B. borini (dominance 22.07 %, prevalence 8.00) and Ph. montani (dominance 22.07 %, prevalence 10.6). All six chewing lice species were observed for the first time in Voronezh and the Central Black Soil Region of Russia. Three species of fleas – Ceratophillus gallinae (Schrank, 1803), C. fringillae Walker, 1856, and C. tribulus Jordan, 1926) – were registered. The dominant flea species was C. gallinae (for the House Sparrow, dominance was 67.13 %, prevalence 45.00; for the Tree Sparrow, dominance was 66.47 %, prevalence 73.33). Abundance of fleas for House Sparrow nestlings was 0.724, and 1.153 for Tree Sparrow nestlings. Parasitic flies were represented by five species: Ornithomya avicularia (Linnaeus, 1758), O. fringillina Curtis, 1836, O. chloropus Bergroth 1901 (Hippoboscidae), Protocalliphora azurea Fll., 1817, and Trypocalliphora braueri (Hendel, 1901) (Calliphoridae). Among louse flies O. avicularia was the dominant species (for House sparrow, dominance was 85.93 %, prevalence 53.00; for Tree Sparrow, dominance was 68.64 %, prevalence 20.00). Larvae of P. azurea were found in 13.00 % of House Sparrow nests and in 15.00 % of Tree Sparrow nests. For House Sparrow nestlings, intensity was 3.42 % with abundance 0.30, while for Tree Sparrow nestlings, intensity was 0.15 % with abundance 2.05. Larvae of T. braueri were found in 31.00 % of House Sparrow nests and in 40.00 % of Tree Sparrow nests. For House Sparrow nestlings, intensity was 0.164 with abundance 0.088. For Tree Sparrow nestlings, intensity was 0.106 with abundance 0.220. Significant fluctuations of prevalence and abundance of the larvae in different years were found.

Insect parasites in multicomponent systems and development of new bioinsecticides

Stable and dynamic interactions among plants, herbivorous insects, parasites and associated microbes are formed in natural habitats. The study of these interactions in multicomponent models is required to develop integrated methods for the management of insect pest populations. In this work, we summarize our studies on the influence of different factors, such as hygrothermal conditions, host development, host microbiota, plant quality, and concomitant infections, on interactions between insects and their parasites, such as fungi, bacteria, viruses and parasitoids. Some approaches for developing complex products for biocontrol are also discussed. For example, the use of natural compounds with immunosuppressive effects may enhance the efficacy of microbial agents toward pest insects.

Associations between Fossil Beetles and Other Organisms

The present work reveals plant and animal associates of 16 families and subfamilies of fossil beetles that have been preserved in amber from Mexico, the Dominican Republic, and Myanmar. The associates include mites, pseudoscorpions, spiders, insect parasites and predators, fungi, angiosperm parts, vertebrates, and nematodes. The presence of these fossil associates can be attributed to the rapid preservation of organisms in resin, thus maintaining natural associations almost “in situ”. Examples of present-day associations similar to those of the fossils show that specific behavioral patterns are often far more ancient than the specific lineages involved.

Host-Specific Activation of Entomopathogenic Nematode Infective Juveniles

Entomopathogenic nematodes (EPNs) are potent insect parasites and have been used for pest control in agriculture. Despite the complexity of the EPN infection process, hosts are typically killed within 5 days of initial infection. When free-living infective juveniles (IJs) infect a host, they release their bacterial symbiont, secrete toxic products, and undergo notable morphological changes. Collectively, this process is referred to as “activation” and represents the point in a nematode’s life cycle when it becomes actively parasitic. The effect of different host tissues and IJ age on activation, and how activation itself is related to virulence, are not well understood. Here, we employed a recently developed bioassay, which quantifies IJ activation, as a tool to address these matters. Appreciating that activation is a key part of the EPN infection process, we hypothesized that activation would positively correlate to virulence. Using the EPNs Steinernema carpocapsae and S. feltiae we found that EPN activation is host-specific and influenced by infective juvenile age. Additionally, our data suggest that activation has a context-dependent influence on virulence and could be predictive of virulence in some cases such as when IJ activation is especially low.

A survey investigating the diversity and distribution of entomopathogenic nematodes in the UK and the first confirmed UK record of Steinernema carpocapsae

Summary Entomopathogenic nematodes (EPN) of the families Steinernematidae and Heterorhabditidae are lethal insect parasites that have been commercialised as biological control agents. EPN have been isolated from across the world but it has been more than 20 years since the last survey of the UK, and species like Steinernema carpocapsae have never been found here and positively identified through molecular biology. We collected 518 soil samples from a diverse range of habitats across the UK and baited them with Galleria mellonella to isolate EPN. Dead G. mellonella were placed in White traps and emergent EPN underwent DNA barcoding analyses. From the 518 samples, 3.5% were positive for EPN. No Heterorhabditis species were found, but seven isolates of S. glaseri, one isolate of S. feltiae, eight isolates of S. affine and two isolates of S. carpocapsae were found. This was the first confirmed record of S. carpocapsae in the UK.