J. Manuel Tierno de Figueroa

Freshwater biodiversity in the rivers of the Mediterranean Basin

We review the diversity of freshwater organisms in the Mediterranean Basin (hereafter Med), particularly from streams and rivers. We present available information on the richness, endemicity, and distribution of each freshwater organism group within the Med, and make a comparison with Palearctic diversity. Approximately 35% of known Palearctic freshwater species and more than 6% of the World’s freshwater species are present in the Med. A high degree of endemicity is found in the Med freshwater biota. These data, together with the degree to which many freshwater species are threatened, support the inclusion of the Med among World biodiversity hotspots. Nevertheless, knowledge of Med biodiversity is still incomplete, particularly for some taxa. Regarding to the spatial distribution of species within the Med, the richest area is the North, although patterns differ among groups. A comparison of the ecological and biological traits of endemic and non-endemic species of three riverine groups (Ephemeroptera, Plecoptera, and Trichoptera) revealed that endemic species have several strategies and mechanisms to face typical mediterranean-climate conditions, such as drought, when compared to non-endemic species. We briefly analyse the conservation status of the region’s biodiversity. Finally, we present some future challenges regarding the knowledge and protection of Med freshwater biodiversity.

The life history of Serratella ignita (Poda, 1761) (Insecta: Ephemeroptera) in a temporary and permanent Mediterranean stream

Abstract.In mid latitudes, such as the Mediterranean region, one consequence of global climate change will be a progressive shift of permanent to temporary water courses, altering the life histories of present species or making them disappear. Presented here is a study on the life history of a mayfly species, Serratella ignita, in two Mediterranean streams, one permanent and one temporary. The research focuses on life history parameters such as life cycle, nymphal growth pattern, feeding type, biomass and secondary production. The life cycle was univoltine, showing a fast seasonal nymphal growth during four months in the permanent stream and five months in the temporary stream, with a long egg stage with diapause. The cumulated day-degrees during nymphal growth were similar between streams. Both populations behaved mainly as gatherer-collectors, but the population from the temporary stream also played an important role as a scraper. Animal matter was also consumed by nymphs from both populations. Gut content analysis showed that both S. ignita populations were opportunist/generalists, where changes in diet were correlated with size. Biomass and secondary production were notably higher in the permanent stream, but they were also high in the temporary stream. These data show that S. ignita had a high fitness in both streams. Our results support the idea that species such as this one may cope with future global climate change by maintaining, or even increasing, their populations at the expense of more stenoecic species.

Study of Antioxidant Defense in Four Species of Perloidea (Insecta, Plecoptera)

The aim of the present work is to conduct a comparative study of oxidative states in the nymphs of four species of Plecoptera belonging to the superfamily Perloidea: Perla marginata (Panzer, 1799) (family Perlidae), Guadalgenus franzi (Aubert, 1963), Isoperla curtate Navás, 1924, and lsoperla grammatica (Poda, 1761) (family Perlodidae) in relation to their ecological and biological characteristics. For this, the activity of the following antioxidant enzymes was determined: superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione transferase (GST), and DT-diaphorase (DTD), together with lipid peroxidation. Glucose 6-phosphate dehydrogenase (G6PDH) was also determined. The four species studied were selected based on significant ecological and biological differences. The results obtained when studying different indicative parameters of the oxidative state of the nymph of different species showed that each has an important enzymatic antioxidant potential, and that differences among species are conditioned by the duration of the nymphal development period more than by whether they come from permanent or temporary habitats. Thus, Plecoptera, although traditionally considered as typical inhabitants of permanent waters, seem to have sufficient variability in physiological mechanisms, together with behavioral and ecological adaptations, to cope with potentially unfavorable conditions that may occur in temporary waters.

Contribution to the knowledge of the genus Loxosomella (Entoprocta) from the Spanish Mediterranean Sea, with the description of a new species, Loxosomella ameliae sp. nov.

Abstract A study of loxosomatidae inhabiting demosponges of the genera Ircinia and Sarcotragus in the Iberian Mediterranean Sea has shown the occurrence of two species. One of them, identified as Loxosomella pes, is recorded for the first time from Spanish waters and some biometric data of the studied population are provided. The other species is new and is here described as Loxosomella ameliae sp. nov. The existence of a wide field of conspicuous gland cells and some features of the foot and calyx characterize the new species and distinguish it from other cogeneric species. With this new species, a total of five species of Loxosomella reported from sponges are known from the Mediterranean Sea.

Freshwater ecosystems and aquatic insects: a paradox in biological invasions

Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur.

First record of the drumming signals of stoneflies Capnopsis Morton, 1896 and Protonemura Kempny, 1898 genera (Plecoptera, Capniidae and Nemouridae)

The male drumming signal of Capnopsis schilleri is studied for the first time. It is a monophasic call composed of 4–8 beats with a decreasing frequency. In the present paper, the drumming signals of some Protonemura species are also recorded and described for the first time both in males (Protonemura alcazaba, Protonemura meyeri and Protonemura navacerrada) and females (P. meyeri, P. navacerrada and Protonemura pyrenaica). The male call is very homogeneous in all the studied species and they consist of a repetition of 2–11 sequences of 6–31 beats, with an inter‐beat interval ranging from 0.034 to 0.088 s. The females have monophasic long signals consisting of a repetition of 5 to 109 beats with an inter‐beat interval of 0.061 to 0.159 s. It is extraordinary that females produced signals when males were absent, and so the female signal can be also considered as a call and not only an answer, as usually pointed out in stoneflies.

First record of male drumming call of the genus Capnioneura Ris, 1905 (Plecoptera, Capniidae)

The male call of Capnioneura mitis, produced by drumming, is recorded and analyzed for the first time. It also represents the first known signal for the genus. It consists of a highly variable number of beats (2–32) with inter‐beat duration approximately constant along the call, but inter‐beat duration is temperature dependent. Thus, at 13°C the mean inter‐beat duration is 1.397 s (SD = 0.050) while at 21°C it is 1.139 s (SD = 0.093). The call pattern exhibited by this species, as those of the majority of previously studied Capniidae species, can be catalogued as an ancestral or near‐ancestral percussive monophasic signal.

Sclerites in Different Tissues of Mediterranean Echinodermata

Abstract The presence of sclerites in different mesodermal tissues was studied in thirteen species of Mediterranean echinoderms representing the five living classes. In the species of Asteroidea and Crinoidea examined, sclerites were present only in specific tissues. In the species of Ophiuroidea and, especially, Echinoidea and Holothuroidea examined, sclerites were present in almost every tissue, but with considerable variation among species and tissues. Data on sclerite shape, size, and relative abundance (measured as tissue abundance) are presented. The data support the possible functional role of sclerites as reinforcing structures, as well as their possible use as taxonomic characters. Finally, the need of more studies to elucidate the ontogenetic and phylogenetic implications of sclerites is discussed.

The Male Drumming Call of Rhabdiopteryx thienemanni Illies (Plecoptera: Taeniopterygidae; Brachypterainae)

Studies in recent decades have revealed that the group Arctoperlaria (Plecoptera) has developed the most diverse and complex system of vibrational communication known in insects (Stewart, 2001). Within this group, the family Taeniopterygidae includes almost 150 species distributed in the Nearctic and Palaearctic regions (Fochetti and Tierno de Figueroa, 2008), but only the vibrational calls of seven species belonging to two genera, Taeniopteryx Pictet, 1842 and Oemopteryx Klapálek, 1902 (e.g. Rupprecht, 1982; Stewart and Zeigler, 1984; Stewart et al., 1991), have been recorded (Stewart and Sandberg, 2006). These latter authors pointed out that all of the seven species present a percussion (drumming) male call, ancestral to slightly derived (change of beat number and/ or intervals). Nevertheless, the several species of Taenionema Banks, 1905 and Doddsia Needham & Claassen, 1925 that have been tested suggest the possibility that some Taeniopterygidae do not drum (Stewart and Sandberg, 2006). The genus Rhabdiopteryx Klapálek, 1902 has a West Palearctic distribution and includes eleven species (Krno, 2004; Vinçon and Murányi, 2009). One of them, R. thienemanni lilies, 1957 is distributed in the Iberian Peninsula and southern France, and the male drumming call is described for the first time in the present work.

Dynamics of the macroinvertebrate community and food web of a Mediterranean stream

ABSTRACT Here, we analyse the annual dynamics in the diversity and the food web structure of the macroinvertebrate community in a Mediterranean permanent stream. Then, we also tested the validity of different proposed predictive models in their ability to fit our results. We calculated the Shannon-Wiener diversity index, the evenness, several food web properties and the proportion of functional feeding groups throughout the year. Our results showed a great variability of the studied parameters with time, mainly in terms of trophic relationships among macroinvertebrates. Diversity did not fluctuate substantially, but functional feeding groups did. In the same manner, complexity of the food web also varied substantially along the year. Comparisons with the considered models showed that, overall, none of the models predicted accurately the observed values. Nevertheless, within them, at least some estimated relatively realistic values, mainly when considering data monthly. From a functional point of view, collector-gatherers were the most abundant group throughout the sampling period except in autumn, when scrapers were also proportionally important. Predators were present during the entire period but with a low abundance. Thus, this study underlines the importance of considering not only static, but also dynamic data when studying food webs.