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1. Age-dependent increases in mortality have been documented in a variety of species of insect under laboratory conditions. However, while strong statistical evidence has been presented for senescence in vertebrate populations in the wild, we know little about the rate and shape of senescence in wild populations of insects. 2. Odonates (damselflies and dragonflies) provide excellent candidate species for evaluating demographic senescence as they are large enough to be marked individually and they are easily re-sighted without recapture. The prevailing opinion - based entirely on qualitative examination of the declines in log numbers alive with time since marking - is that odonates exhibit age-independent daily survivorship. 3. Here, we examine mark-recapture data on the Azure Damselfly Coenagrion puella over two consecutive seasons. For the first time, we evaluate and compare the fit of quantitative models that not only account for weather-dependent daily variation in daily re-sighting rates, but also age-dependent variation in daily survivorship. 4. Models with age-dependent declines in daily survivorship provide a more parsimonious explanation for the data than similar models without these age-dependent effects. In general, models in which mortality increases in an exponential (Gompertz) fashion explain the mark-recapture sequences more efficiently than a range of alternative models, including those in which mortality increases as a power function (Weibull) or reaches a plateau (logistic). These results are indicative of a general senescent decline in physiological functioning, which is particularly marked after 15 days as a mature adult. 5. Weather (temperature, sun and precipitation) and initial mite load influenced the probability of daily re-sighting. Weather and mite load also influenced daily survivorship, but their effects differed between seasons. 6. Overall, fitting models with age as an explicit covariate demonstrates that odonates do indeed senesce. This contradicts previously held assumptions that Odonata do not exhibit age-dependent survivorship in the wild.

Synopsis An account is given of the occurrence of univoltine and semivoltine individuals in populations of Ischnura elegans and Coenagrion puella in a habitat in south Lancashire.

A previous study has shown that wing size in Coenagrion puella varied considerably along a latitudinal gradient in the UK. Using landmark data from wing images, patterns of shape variation were also determined along the same transect by geometric morphometric analysis of wing shape. Wing shape was uniform at all sites other than those closest to the range margin, which differed significantly. The potential mechanisms that might have generated such between-population variation are discussed.

Summary 1. It is poorly understood which traits translate larval stressors into adult fitness in animals where larval and adult stages are separated by metamorphosis. Although fluctuating asymmetry (FA) is often assumed to do so, especially in insects the relationship between larval stress, adult FA and individual quality is often absent. One suggested hypothesis for this is the higher mortality of low quality (hence more asymmetric) animals during metamorphosis (i.e. developmental selection hypothesis). 2. Here we test this hypothesis and also propose and test an alternative hypothesis where metamorphosis is stressful but not lethal and increases FA of all animals up to a certain level (i.e. stressful metamorphosis hypothesis). 3. We manipulated larval stress (food stress and pesticide stress) and measured FA before and after metamorphosis in the damselfly Coenagrion puella. Additionally, we assessed the relationship between FA and individual quality variables measured at metamorphosis (age, mass and two immune variables: phenoloxidase (PO) and haemocyte number). 4. Before metamorphosis, FA reflected the combination of food and pesticide stress and was negatively related with mass and both immune variables after metamorphosis. These patterns were, however, offset after metamorphosis. Low mortality, not linked to FA during metamorphosis, indicates that developmental selection cannot explain this. Instead, the strong increase in FA up to equal levels across treatments during metamorphosis supports the stressful metamorphosis hypothesis. 5. Taken together, the developmental stage in which FA is measured may critically determine the reliability of FA as an indicator of stress and of individual quality in insects.

1. Mass at emergence is a life-history trait strongly linked to adult fitness. Therefore, when faced with transient food shortage in the larval stage, mass-correcting mechanisms are common. 2. These correcting mechanisms may carry costs with them. On one hand, these costs may be overestimated because they can be confounded with the direct effects of the transient food shortage itself. On the other hand, costs may be underestimated by ignoring physiological costs. Another largely neglected topic is that correcting mechanisms and costs may critically depend upon other stressors that often co-occur. 3. Here, we identify the mass-correcting mechanisms and their associated costs at emergence in the damselfly Coenagrion puella, after being stressed by a transient period of starvation and a subsequent exposure to pesticide stress during the larval stage. We introduce path analysis to disentangle direct costs of starvation and the mass-correcting mechanisms in terms of immune response. 4. As predicted, we found no differences in mass at emergence. Starvation directly resulted in a costly delayed emergence and a decreased immune response at emergence. Mass-correcting mechanisms included a prolonged post-starvation period, reduced mass loss at emergence and compensatory growth, although the latter only in females under pesticide stress. 5. The mass-correcting mechanisms were associated with beneficial effects on investment in immune response, but only in the absence of pesticide stress. Under pesticide stress, these beneficial effects were mostly undone or overruled, resulting in negative effects of the mass-correcting mechanisms in terms of immune response. 6. Our results stress the importance of and introduce a statistical way of disentangling direct costs of starvation and the mass-correcting mechanisms themselves, and the importance of including physiological endpoints in this kind of studies.

Extreme temperatures and exposure to agricultural pesticides are becoming more frequent and intense under global change. Their combination may be especially problematic when animals suffer food limitation. We exposed Coenagrion puella damselfly larvae to a simulated heat wave combined with food limitation and subsequently to a widespread agricultural pesticide (chlorpyrifos) in an indoor laboratory experiment designed to obtain mechanisticinsights in the direct effects of these stressors in isolation and when combined. The heat wave reduced immune function (activity of phenoloxidase, PO) and metabolic rate (activity of the electron transport system, ETS). Starvation hadboth immediate and delayed negative sublethal effects on growth rate and physiology (reductions in Hsp70 levels, total fat content, and activity levels of PO and ETS). Exposure to chlorpyrifos negatively affected all response variables.While the immediate effects of the heat wave were subtle, our results indicate the importance of delayed effects in shaping the total fitness impact of a heat wave when followed by pesticide exposure. Firstly, the combination ofdelayed negative effects of the heat wave and starvation, and the immediate negative effect of chlorpyrifos considerably (71%) reduced larval growth rate. Secondly and more strikingly, chlorpyrifos only caused considerable (ca. 48%)mortality in larvae that were previously exposed to the combination of the heat wave and starvation. This strong delayed synergism for mortality could be explained by the cumulative metabolic depression caused by each of thesestressors. Further studies with increased realism are needed to evaluate the consequences of the here-identified delayed synergisms at the level of populations and communities. This is especially important as this synergism provides a novel explanation for the poorly understood potential of heat waves and of sublethal pesticide concentrations to cause mass mortality

The maintenance of female colour polymorphism in coenagrionids is still an open issue. Here we ask if the three different female morphs of Coenagrion puella represent different reproductive traits in terms of clutch and egg size. Therefore clutch size and egg morphometry of the three female colour morphs were examined. We found that female colour morphs did not differ in clutch or egg size. However, we also found that the female morphs differ in egg shape, with the intermediate morph having more elongated eggs compared to the hetero- and and romorphic females. Our results are discussed in terms of potential different preferences in oviposition substrate.

The degree of urbanisation is rapidly increasing worldwide. Due to anthropogenic impact, urban populations are exposed to higher levels of contaminants and higher temperatures. Despite this, urbanisation is a largely overlooked spatial component in ecotoxicology. We tested in a common garden rearing experiment whether replicated urban and rural populations of the damselfly Coenagrion puella differ in their vulnerability to sublethal levels of a widespread pesticide, chlorpyrifos, in terms of ecologically relevant behaviours (exploration behaviour, activity, boldness and food intake), and to what extent these patterns are affected by temperature (20 and 24°C). Except boldness, all behaviours were affected by previous pesticide exposure. While the pesticide did not affect exploration behaviour at 20°C, it was associated with increased exploration at 24°C, which may reflect an increased toxicity of chlorpyrifos at higher temperatures. Importantly, rural and urban larvae showed consistently different, sometimes even opposite behavioural responses to pesticide exposure. When exposed to the pesticide, rural larvae decreased activity and food intake at both temperatures; urban larvae instead increased activity at both temperatures and only reduced food intake at the high temperature. This suggests that urban larvae were less affected by the pesticide, which would be consistent with a scenario of local adaptation to higher contaminant levels. Our results highlight that urbanisation may be an important factor to arrive at a spatially explicit ecological risk assessment, and may be an ignored reason why studies on the same species may generate widely different vulnerabilities to pesticides. publisher: Elsevier articletitle: Urbanisation shapes behavioural responses to a pesticide journaltitle: Aquatic Toxicology articlelink: http://dx.doi.org/10.1016/j.aquatox.2015.04.002 content_type: article copyright: Copyright © 2015 Elsevier B.V. All rights reserved. ispartof: AQUATIC TOXICOLOGY vol:163 pages:81-88 ispartof: location:Netherlands status: published

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.

Thirty-two species of dragonflies were recorded from Azerbaijan in late spring 2002. We estimate the true species richness to be about 45–50 species. Several of these are first records for the Caucasus region or for the Eastern Caucasus subregion. Two forms of Calopteryx splen-dens were found, separated by the valley of the lower Kura, of which only C. splendens interme-dia occurs in the so-called southern and lower Kura. C. s. orientalis occurs on rivers that drain the Talysh hills directly to the Caspian, but there is some phenotypic evidence of hybridization with intermedia south-west of the Kura, where the lower River Vilescay approaches rather close to the Kura. A few species are salt-tolerant and may be outliers from populations further north and east. Others are derived from Iran. Two members of the Coenagrion puella group are recorded; they occur within 50 km of each other, so that Azerbaijan is part of the zone where the two meet. A blue male of Aeshna cyanea is recorded This may be the ...

In this study we assessed whether individuals of the damselfly species Ischnura elegans and Coenagrion puella that moved between ponds differed in their mean characteristics from individuals that did not move. Overall, the sex (female) and species (C. puella) that spent the most time away from the breeding site was more likely to move between ponds. Ischnura elegans males that dispersed had significantly longer forewings than males that did not, while male C. puella parasitised by water mites were more likely to disperse than unparasitised males. There was no evidence for differences in dispersal rates among the female colour forms of either I. elegans or C. puella. In general, the differences in dispersal characteristics between sexes and species could be explained by underlying variation in activity and mobility. The majority of dispersal between breeding sites by C. puella and I. elegans did not appear to be directed, but probably arose from chance movements occasionally taking individuals to a different pond from which they emerged.

Male-biased operational sex ratios are very common in sexually mature dragonflies. These may be due to differential survival or differences in time spent at the breeding site by the sexes. Because most studies are carried out at the breeding site, these two processes can be measured as survival rates or recapture rates using modern capture–mark–recapture methods. We marked 66 female and 233 male Coenagrion puella, and 137 female and 347 male Ischnura elegans during three capture periods spread over 18 days. Each time an animal was recaptured it was re-marked so that the capture history of any captured animal could be readily identified. We recaptured 131 C. puella and 55 I. elegans at least once. We used the Cormack–Jolly–Seber model to estimate the daily probability of survival and recapture. The probability of recapture was, on average, more than three times higher for male C. puella (0.489) than females (0.133) with significant day to day variation. The daily probability of survival did not differ significantly between the sexes (0.860), with no significant variation among days. In contrast, in I. elegans the probability of recapture did not differ between the sexes (0.139 for the first 5 days; between 0.032 and 0.287 for the final 3 days), but the daily probability of surviving was much higher for males (0.812) than for females (0.579). Assuming that the sex ratio was unity at sexual maturity, the recapture and survival rates predicted well the sex ratio of the sample of C. puella but predicted more males than were observed in the sample of I. elegans. This suggests that male I. elegans may suffer higher mortality than females in the immature stage.

To estimate whether male mate guarding alters the predation risk for females, we conducted experiments in field cages with the damselfly Coenagrion puella. We experimentally compared the risk for females ovipositing solitarily versus in tandem with the male. The backswimmer Notonecta glauca was used as a predator. Owing to the oviposition behaviour of the damselflies, N. glauca only preys on females, therefore it was possible to determine whether the presence of males decreases or increases females' predation risk. Females in tandem were more frequently touched and grasped by N. glauca than solitary females. In most tandem pairs, the female showed the first reaction to the attack and the male responded subsequently. After an attack, most solitary females left the oviposition site but most tandem females stayed. Once grasped by the predator, more solitary females were killed.

Water mites are are very important parasites of aerial stages of aquatic insects. Their larvae parasitize semiaquatic hosts and must detach while the host is in a suitable habitat for reproduction of parasite and host. Therefore, water mites should respond to stimuli indicating this situation. Different stimuli were tested experimentally in the host – parasite system Coenagrion puella – Arrenurus cuspidator in outdoor cages; this method provides exact data on the initial intensity of mite larvae per host. It was found that mites detach during tandem oviposition by the host. The detachment rate does not correlate with the host's sex or with the intensity of mite larvae per host. Ectoparasitic water mites are apparently influenced by the host's condition because mites did not detach from dead hosts even in water. Proximity to water also seems to have an impact: mites exposed at a height of 10 mm above water detached, whereas mites exposed at 25 mm or higher did not. We suggest that detachment of mite larvae is triggered by a group of stimuli associated with the egg-deposition behaviour of the host.

1 The influence of fluctuating asymmetry on lifetime mating success of males of the damselfly Coenagrion puella (Odonata: Coenagrionidae) was investigated. Fluctuating asymmetry was measured as the difference in length of left and right fore and hind wings. 2 Males with more symmetrical wings enjoyed higher lifetime mating success. 3 Larger males, in contrast to a previous study of this species, also had higher mating success. This may be attributed to differences in the weather conditions prevailing at the time of the studies.

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.

1. A simulation model is presented which describes, from field-estimated parameters, the effects of daily survival rate and proportion of sunny days on the lifetime egg production of females of the damselfly Coenagrion puella (L). 2. Lifetime egg production increases with daily survival rate and proportion of sunny days. 3. Estimates of mean lifetime egg production per female in bad and good summers in northern England ranged from 333 to 740. 4. The distribution, as well as the proportion, of sunny days influences lifetime egg production. For a given combination of daily survival and proportion of sunny days, lifetime egg production decreases as the distribution of sunny days becomes more clumped. 5. Lifetime egg production is largely determined by chance; females who begin their mature adult life during a period of sunny weather can produce many times more eggs than those whose mature adult life coincides with cloudy days.

Despite their relevance for risk assessment, the interactive effects of pesticide and predation cues are poorly understood because the underlying behavioral and physiological mechanisms are largely unknown. To explore these mechanisms, we reared larvae of the damselfly Coenagrion puella at three different predation risk levels and a range of environmentally realistic concentrations of three pesticides used worldwide (atrazine, carbaryl, and endosulfan). We compared key development responses (growth rate, developmental time, and final size) against food ingestion, assimilation, and conversion efficiency, and acetylcholinesterase (AChE) activity. Predation risk impaired all endpoints, including AChE activity, while the effects of pesticide stress were smaller for atrazine and endosulfan and absent for carbaryl. The effects of both stressors and their interaction on life history were mostly indirect through resource acquisition and energy allocation. Compensatory physiological mechanisms to pesticide stress (atrazine and endosulfan) were present in larvae reared in the absence of predation stress but were offset under predation stress. As a result, smaller size (atrazine and endosulfan) and lower growth rate (endosulfan) from pesticide stress were only found in the highest predation risk treatment. Our results provide insight as to the conditions under which interactions between stressors are likely to occur: damselfly populations at high density and living in fish ponds will be more affected by pesticides than populations at low densities in fishless ponds. By identifying variables that may shape the interaction between predation stress and other stressors such as pesticides, our mechanistic approach may help to bridge the gap between laboratory and field studies. ispartof: Ecological applications vol:17 issue:7 pages:2111-2122 ispartof: location:United States status: published

Background Colour polymorphisms are widespread and one of the prime examples is the colour polymorphism in female coenagrionid damselflies: one female morph resembles the male colour (andromorph) while one, or more, female morphs are described as typically female (gynomorph). However, the selective pressures leading to the evolution and maintenance of this polymorphism are not clear. Here, based on the hypothesis that coloration and especially black patterning can be related to resistance against pathogens, we investigated the differences in immune function and parasite resistance between the different female morphs and males. Results Our studies of immune function revealed no differences in immune function between the female morphs but between the sexes in adult damselflies. In an experimental infection females infected shortly after emergence showed a higher resistance against a fungal pathogen than males, however female morphs did not differ in resistance. In a field sample of adult damselflies we did not find differences in infection rates with watermites and gregarines. Conclusion With respect to resistance and immune function 'andromorph' blue females of Coenagrion puella do not resemble the males. Therefore the colour polymorphism in coenagrionid damselflies is unlikely to be maintained by differences in immunity.

Observations on cannibalism in outdoor insectaries are presented. The behavioural interactions are described. Cannibalism (in both sexes) occurred only during periods of cold weather. It is hypothesised that intraspecific predation is a switch in food selection due to bad weather conditions.

The emergence patterns were followed closely at a pond E of Braunschweig. The emergence period lasted 24 days and the EM50 was reached after 11 days. Due to its emergence phenology. C. hastulatum is classified as a summer species. The date of emergence was negatively correlated with head width in 9 2 but not in

The sizes of adult damselflies (Coenagrion puella) that were marked at emergence and recaptured as mature adults at the natal pond and at the next nearest pond were compared. In addition the sizes of a much larger sample of animals that were never recaptured were compared with those that returned to breed at the natal pond. There was no statistically significant difference in mass or wing length between adults in either comparison. This result contrasts with a previous study on a coenagrionid species in which, from an equally small sample, some evidence of size-biased dispersal was detected (dispersing adults were larger than those returning).

Lifetime mating success of male azure damselflies (Coenagrion puella) was measured in a natural population. The major determinant of mating success is the number of days a male spends at the breeding site, which is mostly determined by a male's adult lifespan. Long-lived males have a higher mating rate than short-lived males, and daily mating rate increases with age up to 6 days, then falls. Large males live longer, but have a lower daily mating rate than small males. These effects of size are very weak, accounting for no more than 2% of the daily variance in mating success. The only overall effect of size on lifetime mating success is that males at both extremes of the size distribution are more likely to fail to mate. Chance differences in the number of females encountered are sufficient to account for the remaining variance in mating success. The weather is also shown to have a major effect on mating success. We draw attention to the ways in which it may be misleading to draw conclusions about the action of sexual selection from studies of daily, rather than lifetime, reproductive success. We provide evidence to support the view that variance in male reproductive success is neither evidence for sexual selection, nor a measure of its intensity.

SUMMARY. 1. Newly-laid eggs of Coenagrion puella (L.) from a pond near Herzogenburg (Lower Austria) were kept at constant water temperatures (range c.3.5°C to c.28°C)in the laboratory. Hatching success varied with temperature; no eggs hatched below 12°C and nearly all hatched at c.l6°C. Hatching time decreased with increasing temperature and the relationship between the two variables within the range 12–28 °C was well described by a power law. The length of the hatching period was less than 12 days. Hatching times estimated from the power-law equations and those obtained in the field experiments were similar. Therefore both the hatching time and the length of the hatching period in the field could be estimated from the laboratory data for the range 12–28°C. 2. The maximum number of instars from egg to imago was 11; the average body length increment (mm) per moult was proportionately constant at c.26% and Dyar's rule was applicable. The interval between moults decreased with increasing temperature up to the seventh instar and the relationship between the two variables within the range 12–28°C was well described by a power law. The moulting interval for instars 8–11 ranged from 23 to 48 days and was relatively independent of temperature. No moulting occurred at temperatures below 12°C. 3. Larval growth was logistic in the laboratory and variations in mean logistic growth rate (range 0–2.5% length day−1) were related to mean temperature with no growth at temperatures