Distribution of the Iberian Calopteryx Damselflies and Its Relation with Bioclimatic Belts: Evolutionary and Biogeographic Implications

Using bioclimatic belts as habitat and distribution predictors, the present study examines the implications of the potential distributions of the three Iberian damselflies, Calopteryx Leach (Odonata: Calopterygidae), with the aim of investigating the possible consequences in specific interactions among the species from a sexual selection perspective and of discussing biogeographical patterns. To obtain the known distributions, the literature on this genus was reviewed, relating the resulting distributions to bioclimatic belts. Specific patterns related to bioclimatic belts were clearly observed in the Mediterranean region. The potential distribution maps and relative frequencies might involve latitudinal differences in relative abundances, C. virgo meridionalis Sélys being the most abundant species in the Eurosiberian region, C. xanthostoma (Charpentier) in the northern half of the Mediterranean region and C. haemorrhoidalis (Vander Linden) in the rest of this region. These differences might explain some previously described latitudinal differences in secondary sexual traits in the three species. Changes in relative abundances may modulate interactions among these species in terms of sexual selection and may produce sexual character displacement in this genus. C. virgo meridionalis distribution and ecological requirements explain its paleobiogeography as a species which took refuge in Iberia during the Würm glaciation. Finally, possible consequences in species distributions and interactions are discussed within a global climate change context

Introgression and rapid species turnover in sympatric damselflies

<p>Abstract</p> <p>Background</p> <p>Studying contemporary hybridization increases our understanding of introgression, adaptation and, ultimately, speciation. The sister species <it>Ischnura elegans </it>and <it>I. graellsii </it>(Odonata: Coenagrionidae) are ecologically, morphologically and genetically similar and hybridize. Recently, <it>I. elegans </it>has colonized northern Spain, creating a broad sympatric region with <it>I. graellsii</it>. Here, we review the distribution of both species in Iberia and evaluate the degree of introgression of <it>I. graellsii </it>into <it>I. elegans </it>using six microsatellite markers (442 individuals from 26 populations) and five mitochondrial genes in sympatric and allopatric localities. Furthermore, we quantify the effect of hybridization on the frequencies of the genetically controlled colour polymorphism in females of both species.</p> <p>Results</p> <p>In a principal component analysis of the microsatellite data, the first two principal components summarised almost half (41%) of the total genetic variation. The first axis revealed a clear separation of <it>I. graellsii </it>and <it>I</it>. <it>elegans </it>populations, while the second axis separated <it>I. elegans </it>populations. Admixture analyses showed extensive hybridization and introgression in <it>I. elegans </it>populations, consistent with <it>I. elegans </it>backcrosses and occasional F₁-hybrids, suggesting hybridization is on-going. More specifically, approximately 58% of the 166 Spanish <it>I. elegans </it>individuals were assigned to the <it>I. elegans </it>backcross category, whereas not a single of those individuals was assigned to the backcross with <it>I. graellsii</it>. The mitochondrial genes held little genetic variation, and the most common haplotype was shared by the two species.</p> <p>Conclusions</p> <p>The results suggest rapid species turnover in sympatric regions in favour of <it>I. elegans</it>, corroborating previous findings that <it>I. graellsii </it>suffers a mating disadvantage in sympatry with <it>I. elegans</it>. Examination of morph frequency dynamics indicates that hybridization is likely to have important implications for the maintenance of multiple female morphs, in particular during the initial period of hybridization.</p

Esperimenti di modifica del ciclo vitale di Odonati.

Al fine di impiegare le Libellule nella lotta biologica alle zanzare, è importante svincolarsi dalla necessità del prelievo in natura, che, oltre ad impoverire i biotopi sorgente, sarebbe limitato dall’andamento stagionale dei cicli vitali delle singole specie. Quindi, come per numerosi altri insetti impiegati nella lotta biologica è necessario prelevare gli individui da allevamenti ad hoc e riuscire a manipolarne il ciclo vitale per disporre di stoks di individui “pronti per l’uso” da utilizzare nel momento opportuno. In questo quadro abbiamo svolto una sperimentazione riguardante la possibilità di posticipare lo sviluppo embrionale di specie dotate di diapausa allo stadio di uovo appartenenti ai generi Lestes e Sympetrum. Per il genere Lestes sono state raccolte in natura ovature contenute in steli di giunco in biotopi dove era stata controllata l’attività di deposizione degli adulti appartenenti alle specie Lestes virens e Lestes barbarus. Gli steli sono stati raccolti in autunno inoltrato, in assenza degli adulti, e quindi non è, stato possibile determinarne la specie. Gli steli sono stati conservati immediatamente dopo la raccolta al buio e +4 °C, disposti verticalmente, all’asciutto ma sospesi su bacinelle d’acqua, che venivano periodicamente controllate alla ricerca di larve neonate. Per il genere Sympetrum, sono state catturate, sempre in tardo autunno, femmine in deposizione in natura e la deposizione delle uova è stata fatta continuare immediatamente a secco e in tubi con acqua. Le specie indagate sono state: Sympetrum striolatum, Sympetrum meridionale, Sympetrum sanguineum. La quantità di uova per femmina fu molto variabile: da una dozzina a circa 1500 (una S. striolatum). Le uova raccolte sono state poi immediatamente conservate, sia a secco, in bustine di carta pergamena, che in acqua, al buio e a +4°C. A partire dal marzo successivo alla cattura, periodicamente aliquote delle uova venivano riportate a condizioni naturali, in vaschette con acqua, sia quelle conservate a secco che quelle conservate in acqua e osservato l’eventuale schiudersi delle uova. Sia per Lestes che per Sympetrum una aliquota delle uova è stata lasciata in acqua e a condizioni naturali, per controllare il loro sviluppo “naturale”. I risultati hanno mostrato che le aliquote lasciate in condizione naturali hanno schiuso fra fine inverno e inizio primavera, come usuale nei biotopi di origine. Le ovature di Lestes, anche al buio e al freddo, hanno iniziato a schiudere da Febbraio in poi, come quelle lasciate all’esterno. Le ovature di Sympetrum conservate all’asciutto non hanno mai ripreso lo sviluppo, mostrandosi via via più rinsecchite anche se non con altri segni di deterioramento. Quelle in acqua non hanno mai schiuso durante la conservazione al buio e freddo, ma alcune sono state invase da funghi fino alla completa demolizione. Tuttavia l’invasione di funghi avveniva solo nella frazione di uova che avevano mantenuto la colorazione biancastra come alla deposizione, invece di sviluppare, come nella maggioranza dei casi, un apparente rivestimento bruno scuro in meno di una settimana (sempre a +4C°). Le aliquote riportate periodicamente alle condizioni naturali stagionali di luce e temperatura (quindi anche non primaverili), hanno dato neonati anche sino ad un anno di distanza dalla raccolta (S. striolatum). Anche se non è possibile stabilire se un tale ritardo avvenga anche in natura, per un adattamento simile alla “banca dei semi”, tuttavia ai fini dell’utilizzo nella lotta biologica questo dimostra, almeno per S. striolatum, la possibilità di conservare individui vitali per un tempo notevole, e di provocarne lo sviluppo in tempi diversi da quelli usuali

A new Polygordius (Annelida: Polychaeta) from Terra Nova Bay, Ross Sea, Antarctica

Polygordius antarcticus sp. nov. is described from benthic material collected at depths ranging between 31 and 61 m in Terra Nova Bay, Ross Sea, during the 1987-1988 and 1988-1989 expeditions of the Italian National Research Program in Antarctica. This is the first named species of the genus from Antarctic waters. Although no fully mature specimens were available, the new species appears unique in combining the following features: a regular pygidium, inflated and with a single ring of round adhesive pads, a conical prostomium with short antennae (only half as long as the prostomium) and shallow head fold, and a well-developed circulatory apparatus, with circumoesophageal commissures entering the prostomium and long intersegmental commissures insinuating into the ventrolateral compartments of the trunk. These and other significant features were investigated by light and scanning electron microscopy. In the construction of the head and the scheme of the blood system, the new species resembles Polygordius triestinus Woltereck, described by Hempelmann in 1906, an aberrant species inhabiting muddy, anoxic sediments in the Adriatic Sea, but it differs significantly from it in the shape of the mouth (in P. triestinus the upper lip is hypertrophied and strongly protruding) and the pygidium (in P. triestinus this region is stump-like and non-adhesive). The pygidium of P. antarcticus sp, nov. is encircled by 28-30 small adhesive pads, each with 15-20 glandular openings. Preterminal cirri are lacking, as are perianal appendages. The anus is surrounded by six to seven lobes of which the midventral is largest and longest. A world distribution map of the genus is provided

The alternative stable state concept and the management of Apennine mountain ponds.

1.In mountainous areas of the central Apennines, permanent ponds and small lakes show high concentrations of nutrients causing algal blooms and fish kills. Their degraded condition is at odds with their conservation status since most of them are located within protected areas. Therefore, urgent remedial measures and management of these valuable habitats is required.2.The concept of alternative equilibria potentially provides a scientific framework for management actions in shallow freshwater ecosystems. However, little is known regarding how this concept applies to Apennine ponds.3.This paper examines nutrient, phytoplankton biomass, transparency and macrophyte data from 30 Apennine ponds and shallow lakes. Patterns of soluble reactive phosphorus, dissolved inorganic nitrogen, chlorophyll a and water transparency are consistent with the existence of alternative stable states. The extent of macrophyte cover plays a key role in stabilizing one of the alternative stable states.4.Reducing nutrient inputs from the catchment

The Ecology and Conservation of Mountain Ponds in Central Apennines, Italy

In mountainous areas of the central Apennines, permanent ponds and small lakes show high concentrations of nutrients causing algal blooms and fish kills. Their degraded condition is at odds with their conservation status since most of them are located within protected areas. Therefore, urgent remedial measures and management of these valuable habitats is required. The concept of alternative equilibria potentially provides a scientific framework for management actions in shallow freshwater ecosystems. However, little is known regarding how this concept applies to Apennine ponds. This paper examines nutrient, phytoplankton biomass, transparency and macrophyte data from 30 Apennine ponds and shallow lakes. Patterns of soluble reactive phosphorus, dissolved inorganic nitrogen, chlorophyll a and water transparency are consistent with the existence of alternative stable states. The extent of macrophyte cover plays a key role in stabilizing one of the alternative stable states. Reducing nutrient inputs from the catchment, adopting measures to increase and/or restore macrophyte beds, and manipulating fish assemblages are potentially promising strategies for the restoration and conservation of Apennine ponds.JRC.H.5-Rural, water and ecosystem resource

Life history and species composition of the damselfly assemblage along the urban tract of a river in central Italy

The species composition of the damselfly assemblage and the life history patterns of two Coenagrionidae (Ischnura elegans and Cercion lindeni) were investigated along the urban tract of a river characterized by increasing organic pollution. The assemblage was dominated by generalist species, usually recorded in lentic habitats, rather than by typical riverine species and the proportion of the latter decrease at the most polluted sites. At the end of Winter, the mean size and instar distribution were different between the sampling sites showing that the life history of both species examined were influenced by a degradation of the environmental quality. A longer reproductive period, absence of diapause, and tolerance of low oxygen concentration appear to be key factors that allow generalist species I. elegans and C. lindeni to predominate at the polluted sites

Nutrient and chlorophyll a temporal patterns in eutrophic mountain ponds with contrasting macrophyte coverage.

In shallow lakes, macrophytes have important effects on food webs, community structure and nutrient dynamics. For this reason they play a significant role in the restoration of degraded systems. Particularly when present with large coverage, they establish mechanisms favoring low phytoplankton biomass and a decrease of nutrient concentration in the water column. Even if these effects are documented from a number of systems, little evidence comes from shallow mountain lakes. In this study, we report temporal patterns of phytoplanktonic chlorophyll a and nutrient concentration in six eutrophic mountain ponds showing contrasting macrophyte coverage. Six ponds, situated in the Italian Apennines at altitudes ranging from 1164 to 1604 m, were monitored from March to November 1997. Four subsurface water samples were collected at each pond on every visit and analysed for chlorophyll a and nutrients following standard methods. Ponds were divided into two groups: vegetated (VP) and unvegetated (UP) according to their summer macrophyte coverage (respectively > 30% and < 30% of pond area). A nested ANOVA was used to detect macrophyte coverage, season and date (nested within season) effect on phytoplanktonic chlorophyll a concentration, dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP). Chlorophyll a was affected by coverage (P < 0.01) and by season (P < 0.05). In both groups chlorophyll a concentration increased from spring to summer, but differences were higher in UP than in VP. DIN was affected by coverage and season but temporal pattern was not consistent among UP and VP (interaction among coverage and season was significant, P < 0.01). SRP was not affected by coverage (P = 0.158) and season (P = 0.169). Our results on mountain ponds are consistent with those of similar lowland systems. We conclude that managing the presence of macrophytes can be an effective tool for the restoration of eutrophic shallow lakes also in mountain areas

Description of the last instar larva of Orthetrum hintzi Schmidt, 1951, and comparison with other African Orthetrum species (Anisoptera: Libellulidae)

The ultimate instar larva is described and illustrated from specimens collected in the streams nr York, Sierra Leone. It is the smallest of the known Orthetrum larvae, from which it can be separated by the presence of dorsal abdominal spines on S7. The main larval features in 8 African Orthetrum spp. are briefly reviewed