The green peach aphid, Mysuz persicae is a parasitic aphid and a commonly found polyphagous insect. It can cause direct and indirect damage to many plant families, including cruciferous crops, by feeding on plant sap and transmitting plant pathogens. The aphid infestation can trigger the host plant, such as cabbage to release different volatile organic compounds (VOCs) and parasitoids can use some of these compounds as chemical markers to distinguish their hosts. Some compounds were discovered in both infested and uninfested cabbage using headspace solid microextraction (SPME) coupled with GC-MS technology. According to the GC-MS report, VOCs released from infested and uninfested cabbage plants varied quantitatively and qualitatively. In a Y-tube olfactometer bioassay, M. persicae attracts both infested and uninfested plants, and the parasitoids Aphelinus abdominalis and Aphidus colemani prefer infested plants to uninfested plants.

Hymenopteran insects, including bees, wasps, and ants, are crucial species of our ecosystems and fulfill valuable ecological roles in nature, as well as in agricultural and industrial activities. With recent reports on dramatic global declines in population size for both bees and wasps, there is an urgent need to understand their circadian system, since it is essential for orientation, foraging, and anticipation of the environment (Eban-Rothschild and Bloch, 2011). A key component in circadian system regulation is light. In Drosophila, the light input pathway involves the light-sensitive protein – cryptochrome (CRY) by inducing protein degradation (Katz and Minke, 2009). In mammals, a non-light sensitive CRY is present and the light input pathway is through CREB by inducing period (PER) expression (Chauhan et al., 2017). However, for other insect species like hymenopterans, that possess only non-light sensitive CRY, the mechanisms behind circadian light entrainment remain unclear. We hypothesize that there may be light-driven circadian gene induction in hymenopteran insects, similar to what has been reported for mammals. To investigate this hypothesis, we have subjected Nasonia to different light conditions and conducted an RNA-sequencing experiment to identify any light-induced gene expression. Our results provide a better understanding of the molecular mechanisms underlying the circadian light input pathway in hymenopterans as well as insight into the possible disruption of circadian entrainment by artificial light in hymenopteran insects.

The lime leafminer Phyllonorycter issikii (Kumata) is an invasive micromoth from East Asia that nowadays is found across the most part of the Palearctic. Known as a pest of limes Tilia spp. (Malvaceae), it is able to outbreaks in both native and urban plantings. The moth was recorded in Western Siberia, in Tyumen Oblast in 2006 for the first time (Gninenko, Kozlova, 2006). Two years later, it was detected further, in Novosibirsk Oblast (Kirichenko et al., 2009), where nowadays it noticeably damages the native small-leaved lime Tilia cordata.

In the end of June 2020, we documented numerous mines of Ph. issikii on lime trees in the Central Siberian botanical garden SB RAS (Novosibirsk). Despite the pest prefers to develop on shaded leaves in the lower part of tree crown (Ermolaev, Sidorova, 2012), in the studied year in Novosibirsk the mines were found on the leaves across the whole tree crown, with the maximal density in its lower part. The mines were also detected on upper side of leaves and on bracts. In mass rearing experiment in laboratory conditions, up to 70% of pupae successfully developed to adults. The rest 30% of the late instar larvae and pupae died, among which only 7.4% of the moth’s individuals were parasitized. We will discuss the composition of native parasitoids attacking the invasive moth and their ability to control the alien pest in the occupied part of Siberia.

The study is supported by the Russian Foundation for Basic Research (No. 19-04-01029-a).

In the last decade, extracellular RNAs have been unravelled as key players in cell-to-cell communication. In this respect, extracellular microRNAs have been thoroughly studied in mammalian systems; and RNA-based inter-cellular, inter-species and even inter-kingdom communication has been demonstrated. Nevertheless, studies reporting on extracellular (mi)RNAs in insects are scarce. Therefore, we have focused on unravelling the presence of ex-miRNAs in this group of animals. Specifically, we have demonstrated that ex-miRNAs are encapsulated in extracellular vesicles (EVs) or associated with Argonaute-1 in cell-free conditioned media of two Drosophila cell lines. In addition, we have found evidence for the selective secretion of miRNAs into EVs. Next, in order to start investigating these matters in vivo, we aimed at optimizing the isolation of EVs from hemolymph. EV purification from this complex biofluid is a challenging task, mainly due to the presence of contaminating (lipo-)proteins. We successfully developed a procedure to isolate EVs from locust hemolymph. Moreover, our results indicate that this approach can be adequate for EV isolation from a wide range of insect species. Given the current lack of standard and robust methods for EV isolation from insect hemolymph, our procedure constitutes an important step towards the advancement of this emerging research field. Our findings open new avenues to further research on insect extracellular RNAs, a so far underexplored but very fascinating topic.

Foraging behavior in animals is based on the interaction among different factors, such as their nutritional requirements, satiety, reproductive state, food composition and presence of various chemicals in the immediate environment. Food preference depends on complex interactions between environmental and physiological cues, and is affected by sensory experience and metabolism during lifespan. In fruit flies, olfaction is considered as one of the main mechanisms used in detection of environmental cues and further behavior adjustment, including food choice. In this work, preference for a particular food in Drosophila melanogaster reared on standard cornmeal substrate was investigated. Virgin males and females were tested individually and in the groups, separated by sex, for food choice. Starving flies had the opportunity to choose between standard cornmeal, tomato, banana, carrot and apple substrates, for one hour. Food choice was monitored in transparent plastic boxes (dimensions: 220 × 140 × 90 mm), containing five Petri dishes (30 mm in diameter), filled with five above mentioned substrates. Males and females did not significantly differ in food choice, both when tested individually or in groups. However, flies chose standard cornmeal, tomato and banana substrates significantly more often than carrot and apple substrates. We previously determined that apple substrate had the lowest quality. Since flies live, eat, mate and lay eggs on fruits and vegetables, avoiding low-quality food has certain advantages in fitness components.

Modern agriculture has numerous consequences, such as soil degradation, toxicants
accumulation and toxicity for non-target organisms. For this reason, researchers refer to the
discovery of harmless pest control tools as an alternative to synthetic insecticides. A solution
might be a natural origin compounds such as plant-derived substances. Among them are
plants secondary metabolites, which may be bioinsecticides, due to their biological activity
like inhibition of food intake or insect growth and development.

Insects can produce many eggs, so oogenesis and oviposition could be the worthwhile aim
of pest control. This study aimed to evaluate the influence of four plant metabolites: (E)-2-
decenal, furfural, 2-undecanone and (E,E)-2-4-decadienal on ovarian development, taking into
account the morphology of final oocytes, the number of eggs and larvae hatching the Tenebrio
molitor beetle, a common storage pest. We used compounds in 2 concentrations: 10^-5
and 10^-7M injected into an adult females insect.

We showed a significant decrease in the volume of terminal oocytes after application of 2-
undecanone at concentration 10^-5 M and an increase for (E,E)-2-4-decadienal and furfural
treatment. In the lower concentration of chemicals, we noted a gentle drop in the volume of
terminal oocytes only after (E)-2-decenal. In each case, follicle epithelium was well
developed. We observed a significant decrease in the number of laid eggs only for the 2-
undecanone in the lower concentration 10^-7 M. In any other case, there were no significant
changes. Moreover, the number of hatching larvae after application tested compounds in 10^-5
and 10^-7 M dose was lower as an effect of lying unfertilized eggs by females.

Obtained results suggest a disturbing effect of tested compounds on pests reproduction

Carabids (Coleoptera: Carabidae) act as agents in biocontrol against pest species in agroecosystems and forestry. Studies have shown that exposure to pesticides can cause lethal and sub-lethal effects on behavior and physiology, which can impact predation efficiency. Neonicotinoids are widely used insecticides that in lower concentrations cause nervous stimulation, while higher concentrations cause paralysis and death in targeted groups of arthropods. Here we test the impact of thiamethoxam on the feeding rate and locomotion of a predatory carabid, Abax parallelus. Beetles were caught in Zagreb County, Croatia. Every individual was weighted and exposed to thiamethoxam (0, 3.9, 9.1, 20, 40 mg A.I./L, based on preliminary studies) by dipping method for 15 s. Two hours after treatment each beetle was offered fresh blowfly larvae and left to feed for twelve hours. Larvae were weighed before and after the feeding, and the mass of the consumed food per body weight was calculated for each beetle. The locomotor ability was tested by turning a beetle on its back and observing the reaction 4, 12, 24, and 48 hours after the treatment. They were classified as normal, slightly intoxicated, intoxicated, and dead/moribund. The results show that groups treated with higher concentrations had significantly lower feeding rates and a higher share of intoxicated and moribund individuals. Feeding rate and locomotion did not differ significantly between control and groups treated with lower concentrations of thiamethoxam. To conclude, short-term exposure to thiamethoxam can result in negative sub-lethal effects, while the effects of long-term exposure to lower doses require further research.

Colleterial glands are female accessory glands occurring in several insect lineages and may display different functions. Within Dictyoptera, they synthesize compounds present in the ootheca of cockroaches and mantises. However, their morphology and secretory activity in Isoptera have been poorly investigated hitherto. Here, we conducted a morphological and histochemical analysis on these structures in different-aged females of Coptotermes gestroi. Thus, isolated abdomens from female alates (non-egg-laying) and 4-yr-old queens (egg-laying) were processed for routine histology. Moreover, xilydine-Ponceau and PAS histochemical tests were applied for identification of total proteins and glycoproteins, respectively. Additionally, the colleterial glands were isolated from 2-d-old (non-egg-laying) and 80-d-old (egg-laying) queens, and measured using the software ImageJ. Colleterial glands are composed of anterior and posterior glands, which are distally ramified but discharge in a common basal trunk. The anterior glands are always longer than the posterior ones, although the epithelium of the latter structures was thicker. The epithelium of both glands increases significantly in width in egg-laying-queens (P<0.01, t-test). Histological sections show colleterial glands poorly developed in female alates, while they are well-developed and extended deeply into the abdomen in 4-yr-old queens. Histochemical analysis evidenced proteinaceous secretion in the lumen of both glands in female alates. However, glycoproteinaceous granules occurred only in the lumen of the posterior glands in 4-yr-old queens, while they were absent in the lumen of anterior glands. The results suggest modification in the chemical nature of the secretion of the colleterial glands during the queen life, especially associated to the oviposition process.

Insects are the most evolutionarily and ecologically successful group of living animals, being present in virtually all possible habitats on the mainland, but virtually absent in the ocean which constitute 90% of the biosphere. Only a few species are present in the sea, but remaining at the surface, salt marshes, estuaries, or shallow waters. Remarkably, a group of 13 species manages to endure long immersion periods in the open sea, as well as deep dives, i.e. seal lice. Sucking lice (Phthiraptera: Anoplura) are ectoparasites of mammals, living into the fur or among the hairs of their hosts. Among them, the family Echinophthiriidae is peculiar in the sense that it infests amphibious hosts, such as pinnipeds and otters, who can perform deep dives and remain with their bodies submerged from several weeks to several months. During the evolutionary transition of pinnipeds from land to the ocean, echinophthiriids lice had to manage the amphibian biology of their hosts, some of which may spend more than 80% of the time submerged and performing extreme dives at beyond 2000m under the surface. These obligated and permanent ectoparasites have adapted to tolerate hypoxia, high salinity, low temperature, and, in particular, to tolerate conditions of high hydrostatic pressure. We will discuss some of these adaptations allowing seal lice coping with the amphibious habits of their hosts and how they can help understanding why are insect so rare in the ocean.

Feijoa (Feijoa sellowiana [Berg] Burret) has been cultivated in both agroforestry and monoculture systems in the southern region of Brazil. However, little is known about the occurrence of pests related to this culture in such region, especially in agroecological production systems. Within the economical relevant insects, fruit flies (Diptera: Tephritidae) occupy a concerning status to many producers. In this context, we aimed to monitor the presence of tephritides in F. sellowiana fruits produced under two different agroecological conditions, a monospecific cultivation and an agroforestry system. It was installed 30 traps on F. sellowiana trees, and their content collections executed every 10 days during the fructification period of 2019/2020 harvest, when it was also removed fruits to monitor the fruit flies larva. Additionally, it was measured the parameters related to plant height, crown and trunk tree circumferences, as well as the plant productivity. In total, 1805 individuals were collected from the fruit fly traps, with a higher occurrence in the monospecific cultivation. It was observed a sexual ratio of 3.74 females for 1 male. About the larval monitoring, the infestation index was 11.86 pupae/fruit to the agroforestry system and 15.4 to the monospecific one, with a pupal feasibility of 25.84% and 11.26% to these areas, respectively. It was not observed statistical significance in relation to plants size parameters and occurrence of fruit flies in the monitored areas. In general, was observed lowest occurrence of fruit flies in the agroforestry system, suggesting the viability of cultivating feijoa in biodiverse systems.