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Abstract: Two of the main functions of the immune system are to control infections and to contribute to wound closure. Here we present the results of an RNAseq study of immune- and wound-response gene expression in the damselfly Coenagrion puella, a representative of the odonates, the oldest taxon of winged insects. De novo assembly of RNAseq data revealed a rich repertoire of canonical immune pathways, as known from model insects, including recognition, transduction and effector gene expression. A shared set of immune and wound repair genes were differentially expressed in both wounded and immune-challenged larvae. Moreover 3-fold more immune genes were induced only in the immune-challenged treatment. This is consistent with the notion that the immune-system reads a balance of signals related to wounding and infection and that the response is tailored accordingly. [Copyright &y& Elsevier]

1. The extent to which individuals are parasitised is a function of exposure to parasites and the immune response, which in ectotherms may be associated with temperature. 2. We test the hypothesis that seasonal variation in ectoparasite burden is driven by temperature using an extensive mark-release-recapture study of adult Coenagrion puella (L.) (Zygoptera) as a model system. Mite counts were taken both at capture and on a subset of subsequent recaptures over two entire, consecutive breeding seasons. 3. Emergence date was the most significant factor in determining individual differences in mite burden, and mean counts for individuals emerging on the same days showed strong unimodal relationships with time of season. Subsequent recounting of mites on a subset of individuals showed that patterns of loss of mites were similar between seasons. 4. While temperature did not significantly affect mite burdens within seasons and ectoparasite prevalence was very similar across the two seasons, intensity of infection and rate of mite gain in unparasitised individuals were significantly higher in the cooler season. 5. We demonstrate that, while temperature may modulate the invertebrate immune response, this modulation does not manifest in variations in mite burdens in natural populations. [ABSTRACT FROM AUTHOR]

By a combination of detailed behavioral observations and molecular genetic approaches we have assessed development time, timing of first maturity, and the extent of genetic structure through the flying season in a wild population of the damselfly Coenagrion puella in England. This work provides the first estimate of development time (egg to mature adult) in the field based on individual damselflies. Development time was significantly longer for females than males. In contrast to reported laboratory studies, there was no difference in development times between different female color morphs. Development time ranged between 347 and 396 days and was negatively correlated with egg-laying date. As a result eggs laid early in one season reach adult maturity relatively late in the next; concurrently individuals developing from eggs laid late mature relatively early. We speculate that this pattern of development is a direct physiological response to seasonal environmental variation and results in reproductive synchrony within a population. Size, specifically hind wing length, declined with development time in males, but not in females. In one of the two years of the study there was evidence for weak clustering of related individuals during the reproductive season. This appeared to be the result of developmental synchronization within families: variance in timing of maturation was smaller in full-sib families than in half-sib families or randomly assigned unrelated groups. [ABSTRACT FROM AUTHOR]

The article presents a study on sublethal pesticide concentrations and predation. It examined larvae of the damselfly Coenagrion puella in three predation risk levels with three pesticides including carbaryl, atrazine, and endosulfan. The study recorded the development of the larvae with regards to developmental time, growth rate, and final size. It also examined the larvae regarding food ingestion, acetylcholinesterase activity, and conversion efficiency. The study found that predation risks and pesticides indirectly affected the larvae. It concluded that dense damselfly populations in fish ponds will be more affected by pesticides than lower density populations in fishless ponds.

Damselflies provide a classic example of female colour polymorphism. Usually, one female morph resembles the blue male colour (andromorph) while one, or more, female morphs are seen as typically female (gynomorph). Damselfly species fall in two distinct groups with respect to recent developments in mimicry theory: in some species females are perfect, they match male colouration and black patterning, and in other species they are supposed to be imperfect mimics, only matching male colouration. However, the underlying assumption of one female morph looking male-like is mostly based on human vision. Therefore we investigated the black patterning and colour of the three female morphs in Coenagrion puella, an imperfect mimic, using image analysis. In C. puella the blue female morph is perceived as male-like. We found that the black patterning of such females cannot be distinguished from the other female morphs, and is clearly different from males. Furthermore, the blue colour of andromorph females differs from the blue colour of males. Intriguingly, however, the red content did not differ between blue males and females. [ABSTRACT FROM AUTHOR]

Summary1. A simulation model investigating the co-evolution of water mites infesting their aquatic insect hosts during emergence is presented. The model is based on field and experimental studies of the ectoparasitic water mite Arrenurus cuspidator and the damselfly Coenagrion puella. 2. Three scenarios were studied: (1) Only the host was allowed to evolve timing of emergence, while the timing of the parasites' infestation opportunity was held constant. (2) Both host and parasite were allowed to evolve. (3) Only the parasite's timing was allowed to evolve, while the host was constrained completely. 3. In the first two scenarios, parasite abundances decreased in the course of evolution and reached values well below those found in the field, whereas in the third scenario, parasite abundances were maintained at a level close to that found in the field. In the second scenario (co-evolution), the host seemed to be the leader in the evolutionary race. 4. It is concluded that water mite parasitism is capable of shaping emergence patterns in aquatic insects and, despite the same life-cycle length for host and parasite, the parasite evolves fast enough to shape its hatching pattern to match the emergence pattern of its host. [ABSTRACT FROM AUTHOR]

Coenagrion puella males search actively for mates and are not aggressive to other males. To study the role of visual cues in male–female discrimination, four types of models were used: (1) bodies of intact insects, (2) models of painted males, (3) models of male–female chimerae, and (4) models of female body parts. Abdomen coloration pattern and presence of wings were the most important cues for sexual recognition by males. Step-by-step elimination of male coloration pattern leads to an increase in the tandem response rate. A female model painted as a male repelled males like the intact male model. The absence of either the head or the thorax slightly decreased the number of tandem responses, but models without both the head and the thorax were not recognized as a mate. Abdomen thickness larger than that of a normal female decreased the attractiveness of the model. Models of the gynochrome female were significantly more attractive than models of the androchrome one. Female models containing male parts were less attractive than models without any structure at this place. Using principal-components analysis, it is shown that models repelling males usually were those containing an intact male abdomen or a female abdomen painted with blue. The results indicate that C. puella males can distinguish males from females visually by morphological structures and coloration pattern. [ABSTRACT FROM AUTHOR]