New data on the Odonate fauna from Graciosa Island (Azores)

[…]. Currently, four odonate species are known from the Azores archipelago (Valle 1940; Gardner 1959, 1960; Belle 1992; Cordero-Rivera et al. 2005; Lorenzo-Carballa et al. 2009), namely, Anax imperator Leach, 1815 (Aeshnidae), Sympetrum fonscolombii (Selys, 1840) (Libellulidae), Ischnura pumilio (Charpentier, 1825) and Ischnura hastata (Say, 1839) (Coenagrionidae). The first three species belong to the European fauna, whereas the last one is native to the Americas (Belle & van Tol 1990; Lorenzo-Carballa et al. 2009; Weihrauch 2011). In a previous paper we found that all four species were known from all islands except Santa Maria and Graciosa, but we proposed that this was due to a lack of sampling and suggested that it is likely that all four species are present in all of the nine islands (Cordero Rivera et al. 2005). Further sampling confirmed the presence of these four species in Santa Maria Island (Lorenzo-Carballa et al. 2009; Tavares et al. 2010). Very few records of odonates have been published for Graciosa. The first was a female S. fonscolombii observed on July 17, 1938 (Valle 1940). No indication of the relevant locality was given. To our knowledge, only A. imperator and S. fonscolombii species were further recorded for Graciosa (Cordero-Rivera et al. 2005; Lorenzo-Carballa et al. 2009), but again without localities. So, the present contribution deals with new odonate records for this island. Given that I. hastata is of great interest in every island of the archipelago due to its unique parthenogenetic reproduction in all its Azorean localities, the first author made two visits to Graciosa in 2004 and 2007, in order to survey the local odonate fauna

Sex wars: a female genital spine forces male damselflies to shorten copulation duration

In some species, males use weapons to harm females, increasing their short-term fitness. Here we show that females can use genital adaptations against males. Females of the damselfly Enallagma cyathigerum have a conspicuous vulvar spine on the eighth abdominal segment, which contacts with the male during copulation. We tested 3 hypotheses for its function: it (a) inflicts damage to the male during copulation; (b) facilitates endophytic oviposition; and (c) stimulates males during copulation to increase their investment. We found that males mated on average for 54 min with control females, but increased copulation to 99 min with females without spine. There was no evidence of physical harm of the spine on the male’s seminal vesicle, which shows 8- to 18-folds, exactly where the spine contacts during copulation. Females with and without spine exhibited the same egg-laying rates and showed similar fecundity and fertility. Longevity was also similar in males mated to control and spineless females. In contrast to many species where females resist male harassment by behavioral responses, the morphological adaptation observed in E. cyathigerum appears to act as a sexual weapon, allowing females to control copulation duration. We suggest that the spine has evolved because of sexual conflict over mating duration.Universidade de Vigo/CISUGMinisterio de Economía y Competitividad | Ref. CGL2014-53140-PAgencia Estatal de Investigación | Ref. PGC2018-096656-B-I0

Evolution in Islands: contrasting morph frequencies in damselfly populations of the Balearic Islands

Colour polymorphism is an example of visible phenotypic variability that is often associated with ecological factors and may produce local adaptations. Small populations, particularly in islands, offer opportunities for evolutionary novelties, and are therefore of particular interest to the study of polymorphisms. Here we study the dynamics of female colour morphs in the damselfly Ischnura elegans in the Balearic Islands. We found that insular populations are small, show low density, low mating activity, and low androchrome frequency. Our surveys suggest that male harassment is a powerful force in the dynamics of this female-limited polymorphism, because high male densities result in lower presence of mature females around the water, where copulation takes place. Non-male-like (infuscans) females have higher mating frequency. Androchromes were rare (15%) in all populations, but the frequency of the two non-male like females (infuscans and aurantiaca) was reversed between islands, despite their geographical proximity. We found a possible novel morph, suggesting that insular conditions allow innovations. Fitness differences between the two non-male-like females of I. elegans are still understudied, because most previous research has concentrated on the maintenance of androchromes, and are therefore a priority for future research.Agencia Estatal de Investigación | Ref. PGC2018-096656-B-I00Universidade de Vigo/CISU

Incidence of Anagrus obscurus (Hymenoptera: Mymaridae) egg parasitism on Calopteryx haemorrhoidalis and Platycnemis pennipes (Odonata: Calopterygidae, Platycnemididae) in Italy

Very little is known about the incidence of egg parasitoids in odonates, perhaps because Odonata eggs are well protected in stems or leaves, sometimes below water. In Central Italy (Pontecorvo, Frosinone province) two damselflies, Calopteryx haemorrhoidalis and Platycnemis pennipes occur at high densities. In August 2007 we collected 30 stems of the aquatic plant Potamogeton sp. used as substrate for oviposition and incubated eggs in the laboratory. Most stems (24 for C. haemorrhoidalis and 23 for P. pennipes) contained odonata eggs. Parasitoids emerged from 12 stems, with a mean parasitism of 2% for C. haemorrhoidalis and 6% for P. pennipes, and a maximum of 14% and 50%, respectively. Furthermore, we observed egg-laying of 19 females of C. haemorrhoidalis and 11 of P. pennipes, and marked the stems where oviposition was observed. Clutches remained in the river for 5 days and were then collected and incubated. Parasitoids emerged from 11 stems out of 30, with an average parasitism of 8% for C. haemorrhoidalis and 3% for P. pennipes (maximum of 50% and 29%, respectively). All parasitoids belonged to the family Mymaridae, and were identified as Anagrus (Anagrus) obscurus Förster, 1861, sensu Soyka, 1955. This is the first time that such species is described as an egg parasitoid of odonates, and that an egg parasitoid of C. haemorrhoidalis and P. pennipes is identified. Our data suggest that egg parasitism might be a significant selective factor for both odonates in the studied locality, affecting female oviposition behaviour

The evolution and diversity of intra-male sperm translocation in Odonata: a unique behaviour in animals

Behavioural diversity is a basic component of biodiversity, with implications in ecological interactions at the intra- and interspecific levels. The reproductive behaviour of Odonata (dragonflies and damselflies) is unique among insects and conditioned by the anatomical separation between the male’s reproductive organs and the intromittent organ. Prior to mating, males must translocate sperm from the genital pore in the ninth abdominal segment to the seminal vesicle located ventrally in the second abdominal segment. This behaviour, exclusive to odonates, is known as intra-male sperm translocation (ST). Here, we review the literature on ST and use phylogenetic comparative analyses to investigate the evolution of ST within the Odonata. Information on ST was compiled for 176 species, with the commonest variant being ST once per mating, after tandem formation (66%). Other variants found were ST involving precopulatory genital touching (10%), ST by the male alone before tandem (16%) or after copulation (5%), and repetition of ST during the same copulation (3%). The precopulatory genital touching might have evolved to detect female receptivity. ST before tandem formation might be favoured when mating opportunities are scarce and copulations are brief. ST after mating might be favoured if males need to be ready to copulate fast. Finally, repeated ST could have evolved through postcopulatory sexual selection in males with limited sperm removal ability, as a means to improve their sperm competition. The most plausible scenario for the evolution of ST is that the ancestors of the Odonata produced a spermatophore and attached it to the body, leading towards the evolution of the secondary genitalia in males. Our study emphasises the role of behavioural diversity to understand behavioural evolution.Ministerio de Economía y Competitividad | Ref. BES-2015-071965Ministerio de Economía y Competitividad | Ref. CGL2014-53140-

Ischnura praematura sp. nov. (Odonata: Zygoptera: Coenagrionidae): a species from Yunnan (China) whose females mate in the teneral state

Ischnura praematura sp. nov. (Holotype ♂, China, Yunnan, Lijiang, 26º31´03.54”N, 100º13’38.89”E, 2396 m, 04 xii 2015, I. Sanmartín-Villar & H. Zhang leg.) is morphologically described, illustrated and compared with close species of the genus. Ischnura praematura can be mainly distinguished from its congeners I. aurora, I. rubilio and I. asiatica by its abdominal and thoracic morphology and colouration. The posterior lobe of the prothorax is elevated in I. praematura and the mesostigmal plates possess dorsal triangular protuberances. Ischnura praematura shows pointed paraprocts, internalised wide cerci and lacks a dorsal tuberculum in the tenth abdominal segment. The blue abdominal colouration is present in the last three segments (incomplete for segment eight and ten in some individuals). No female polychromatism was detected and all females observed possessed different colouration than male (gynochrome). Morphological distinctiveness of the species is supported by genetic analyses, which show that I. praematura forms a well-supported, monophyletic clade, with I. asiatica, I. ezoin and I. pumilio as the most closely related species. In the field, mature females show strong reluctance to mate, and males were observed mating with newly emerged females.  Ministerio de Economía y Competitividad | Ref. BES-2012-052005Ministerio de Economía y Competitividad | Ref. EEBB-I-15- 09382Ministerio de Ciencia e Innovación | Ref. CGL2014-53140-PMinisterio de Ciencia e Innovación | Ref. PGC2018-096656-B-I0

Sexual conflict and the evolution of monandry: the case of the damselfly Ischnura hastata (Odonata: Coenagrionidae) in the Galápagos Islands

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG1. Sexual selection favours the evolution and maintenance of polygamy, which is the dominant reproductive strategy in insects. Monogamy can evolve in very short-lived species due to time constraints. Here we study adult activity and mating behaviour of a population of the damselfly Ischnura hastata, a species rarely seen mating, and which has been suggested to be monandric, in wetlands of Isabela Island, Galápagos. 2. By means of mark-recapture methods we estimated that the daily survival rate was low, ranging from 0.385 to 0.876, yielding average life expectancies of mature individuals of only 1.2-3.2 days. Adults showed very low activity before 7:00, indicating that mating does not occur early. The number of male-female interactions and mating attempts was extremely low, with only 44 copulations recorded on over 230 h of observations. 3. Copulations were brief, with a mean duration of 11 minutes (but only two observed from the start). Males showed clear preference to attempt to grasp in tandem females of intermediate age (in 94.3% of cases), rather than young (31.3%) or mature females (24.0%). Males were very persistent once a tandem was achieved, retaining females for up to 139 min, but most females resisted and did not copulate. 4. We conclude that females of I. hastata show a very short time window to mate, exactly when they change colour from juvenile to mature, and live only enough to mate once. Short lifespan has selected for female monandry in I. hastata, creating an intense sexual conflict over mating rates.Ministerio de Economía y Competitividad | Ref. CGL2014-53140-PAgencia Estatal de Investigación | Ref. PGC2018-096656-B-I0

Biosociological ethodiversity in the social system

A comprehensive understanding of human sociality needs to embrace the coevolution of genes and culture. Recent advances in biological research about niche construction by organisms, and the development of the concepts of social niche and ethodiversity, can be integrated into a common approach to understand this coevolution, which implies the interaction between sociology and ecology in an integrative framework of knowledge. In this paper the authors propose such inclusive biosociological and heuristic framework to improve the understanding of the evolution of social niche construction. In addition, it allows a better understanding of the concept of sociotype in non-human organisms and explains some aspects of the social or presocial behavior through the concept of ethodiversity.ACR (who is 1% Inuit according to his genes) was funded by a grant from the Spanish Ministry of Science, Innovation and Universities, including ERD funds (CGL-2018-096656-B-100). Funding for open access charge: Universidade de Vigo/CISUG.info:eu-repo/semantics/publishedVersio

Variation in intraspecific sperm translocation behaviour in a damselfly and its consequences for sperm viability

Sperm quality and viability affect both male and female fitness. Most dragonfly and damselfly males translocate sperm from the testis to the seminal vesicle before each copulation, a behaviour known as intramale sperm translocation (ST). However, some published observations indicate that odonate males can occasionally skip ST prior to copulation. Our aim was to determine the circumstances under which males skip ST and how this might affect sperm viability. We allowed males of the damselfly Ischnura graellsii to perform ST (interrupting the copulation at this stage) and we studied ST behaviour during subsequent copulation. Males were randomly assigned to four treatments, which consisted of allowing the experimental male to copulate again 15 min or 1–3 days after his last ST. Fertility of females mated with the experimental males was analysed as a proxy for sperm viability. All males used the sperm that they translocated previously when the second mating took place 15 min after the manipulation, while the proportion of males that repeated ST increased steadily over time. Both treatment (time elapsed since last ST) and the interaction between treatment and ST (yes/no) had a significant effect on fertility, which decreased only in males that did not perform ST immediately before copulation. Additional experiments with damselflies of the genus Calopteryx showed also that males did not repeat ST when the time to the next copulation was less than a day. Our results suggest that sperm quality decays over time in odonates, and that males can choose whether to keep and reuse the sperm in the seminal vesicle or to discard it. We conclude that the special anatomical disposition of odonate males might increase selective pressures to maximize sperm viability and/or repeated intramale ST behaviour.Ministerio de Economía y Competitividad | Ref. BES-2015-071965Ministerio de Economía y Competitividad | Ref. CGL2014-53140-

Alternative reproductive strategies in black-winged territorial males of Paraphlebia zoe (Odonata, Thaumatoneuridae)

Alternative reproductive strategies are commonly associated with male dimorphism. In Paraphlebia zoe, a species of damselfly whose males are dimorphic in wing coloration, black-and-white-winged (BW) males defend territories, while hyaline-winged (HW) males usually play the role of satellites. We found that several BW males can sometimes share a territory, and we hypothesized that within this morph there are two alternative tactics: submissive and dominant. We conducted an experiment to test whether dominant and submissive roles are plastic or stable and fixed on each individual. To this end, we manipulated black and white spots of BW males in four treatments: (i) painting over white and black spots without changing their size, (ii) erasing the white spot using black painting, (iii) increasing the black spot and moving the white spot maintaining its size and (iv) control males. Additionally, we investigated the correlation between some phenotypic variables (wing asymmetry, survival and recapture probabilities) and male behaviour (in terms of quality of the territory). We found that the two behavioural roles (submissive and dominant) were not affected by the manipulative experiments, therefore suggesting that they are stable and fixed. Additionally, we found a positive correlation between body size and survival in both sexes, and a positive effect of territory quality and lifespan on mating success. Moreover, the largest and youngest BW males were the most symmetrical. We conclude that Paraphlebia zoe holds high behavioural diversity, with two types of strategies in BW males, dominant and submissive. The occurrence of this intra-morph behavioural diversity might depend on demographic factors such as population density and/or the relative frequency of the different morphs