José Manuel Tierno de Figueroa

Notes on diversity and conservation of the European fauna of Plecoptera (Insecta)

Plecoptera are one the most endangered groups of insects in running waters. Due to their strict ecological needs and to the growing pollution of water courses, many species are in fact reduced to small isolated populations and many others have already become extinct. With the aim of compiling the taxonomic and faunistic lists of European Plecoptera (within the project Fauna Europaea, ref. EVR1‐CT‐1999‐2001), we catalogued a total of 426 species included in 35 genera and seven families and reviewed their present diversity and conservation status. Historical knowledge and geographical information on Plecoptera diversity in Europe are presented. Data on the conservation status of the European stonefly fauna are discussed as well. The whole Plecoptera fauna of lowland rivers in Europe can be considered threatened. The situation is particularly critical for several species, known from a small number of individuals and/or from restricted areas, and that of relict species. Despite this situation, no European Plecoptera species are included on any official lists of threatened species.

Imaginal Feeding of Twelve Nemouroidean Stonefly Species (Insecta, Plecoptera)

Abstract We studied the gut contents of adults of 12 stonefly species of the superfamily Nemouroidea, belonging to 3 different families: Nemouridae (4 species), Capniidae (2 species), and Leuctridae (6 species) from the Sierra Nevada Mountains in Spain (southern Iberian Peninsula). For each species, we describe the male and female diet. After determining and quantifying the different components, we deduced that feeding is important among adults in this superfamily, and that the diet is varied, with cyanolichens and cyanophyceae being prominent, and hyphae and spores of Ascomycetes sometimes eaten, whereas pollen is amply consumed by some spring or spring–summer species.

Life cycle and nymphal feeding of Rhabdiopteryx christinae Theischinger 1975 (Plecoptera: Taeniopterygidae)

Abstract In the present paper some aspects of the nymphal biology of Rhabdiopteryx christinae, an endemic species from the Iberian Peninsula, are studied in a temporary stream from Southern Spain. R. christinae has an univoltine life cycle, with very short, fast and constant nymphal development, only having four months (December-March), related with the seasonality of the stream. In order to resist the period in which the stream has no water, an egg diapause probably occurs. The study of nymphal gut contents showed that R. christinae acts mainly as collector (detritus) and scraper (epiphytic and epilitic diatoms), as it is generally accepted for the family Taeniopterygidae.

Continental drift and climate change drive instability in insect assemblages

Global change has already had observable effects on ecosystems worldwide, and the accelerated rate of global change is predicted in the future. However, the impacts of global change on the stability of biodiversity have not been systematically studied in terms of both large spatial (continental drift) and temporal (from the last inter-glacial period to the next century) scales. Therefore, we analyzed the current geographical distribution pattern of Plecoptera, a thermally sensitive insect group, and evaluated its stability when coping with global change across both space and time throughout the Mediterranean region—one of the first 25 global biodiversity hotspots. Regional biodiversity of Plecoptera reflected the geography in both the historical movements of continents and the current environmental conditions in the western Mediterranean region. The similarity of Plecoptera assemblages between areas in this region indicated that the uplift of new land and continental drift were the primary determinants of the stability of regional biodiversity. Our results revealed that climate change caused the biodiversity of Plecoptera to slowly diminish in the past and will cause remarkably accelerated biodiversity loss in the future. These findings support the theory that climate change has had its greatest impact on biodiversity over a long temporal scale.

Adult feeding habits of three Perloidea species (Plecoptera: Perlidae and Chloroperlidae)

The gut content composition of three species of the superfamily Perloidea, Marthamea selysii (Pictet, 1842), Dinocras cephalotes (Curtis, 1827), and Siphonoperla torrentium (Pictet, 1842), from northwestern Spain is analyzed and described. The quantity of food found in all adults of M. selysii and D. cephalotes was very low. Spores of fungi and pollen of angiosperms were the most abundant components in the diet of M. selysii. Pollen of angiosperms, followed by fungal spores, detritus, and animal matter were the most abundant components in the diet of both sexes of D. cephalotes. The adult diet of both sexes of S. torrentium consists mainly of pollen and agrees with data of the previous studies on this same species in other areas. Our results also show that the consumption of animal matter could be a way to get a nutritional complement and is more common than previously considered in adult stoneflies. The obtained data support the hypothesis that adult feeding is less important for large stoneflies (as M. selysii and D. cephalotes) than for other smaller Perloidea (as S. torrentium), but feeding habits in these large Plecoptera could not be as negligible as previously supposed.

Intraspecific and interspecific variation in drumming signals in the genus Capnioneura (Plecoptera: Capniidae)

The male drumming calls of four species of the genus Capnioneura, and for the first time, the female answer signal from one species of this genus are described. Only the male call of C. mitis from a southern Iberian Peninsula is known. In the current study, the male calls of three additional C. mitis populations from two different mountain drainages and the male calls of C. gelesae, C. libera and C. petitpierreae are described and analysed. The calls were near-ancestral and percussive signals with variable numbers of beats and approximately constant, monophasic beat intervals. The mean interbeat intervals were species specific, ranging from 250 to 1500 ms. The C. mitis female answer interbeat intervals were similar to the call but composed of 3–4 beats. Intraspecific and interspecific variation is discussed and these results support the hypothesis that stonefly drumming plays an important role as a reproductive isolating mechanism.

The influence of water quality and macroinvertebrate colonization on the breakdown process of native and exotic leaf types in sub-alpine stream

Most of the energy input of low-order lotic food webs derives from non-living sources of terrestrial organic matter. For this reason, many studies have examined patterns of leaf breakdown; most recently, interest has focused on the importance of water quality or the nature (native versus exotic) of plant material. In this study, we combined both aspects by analyzing the breakdown process and macroinvertebrate colonization of leaf bags containing leaves of different plant types in two nearby sites with different levels of water quality. We exposed a total of 600 leaf bags made of five leaf types (three native: Alnus incana, Populus alba and Quercus robur; and two exotic: Reynoutria japonica and Robinia pseudoacacia) at two sites of the Pellice River (northwestern Italy). Leaf bags were retrieved after 10, 20, 30, 40, 50 and 60 days, leaf mass loss determined and the associated macroinvertebrates quantified. Significant differences were found in the mass loss and in the colonization of leaf bags between sites but not between native and exotic species. Dry mass loss was different among species but without any evident relation with exotic or native origin of plants. In our study sites, geographical origin of plant detritus is not per se central in shaping macroinvertebrate colonization and mass loss because the impact of wastewater treatment plant effluent seems to be much more important than plant origin in the breakdown process.

Macroinvertebrate colonization of two different tree species leaf packs (native vs. introduced) in a Mediterranean stream

Allochthonous leaf litter from riparian vegetation represents the main energy source in small lotic systems, where canopy limits autochthonous primary production. In this study, leaf packs of two tree species (the native Salix neotrichia and the introduced Populus x canadensis) were positioned in the Fardes Stream (southern Spain) to analyze the macroinvertebrate colonization. On two dates, leaf packs were removed, and colonizing macroinvertebrates were collected and identified; at the same time, Surber samples were collected to characterize the riverbed macroinvertebrate coenosis. Leaf packs attracted rich and varied communities of benthic macroinvertebrates, with an increase of the abundance of most taxa over time. No significant differences were found between the colonizing communities of the two leaf types. Some macroinvertebrate species showed a preference for leaf packs, probably due to trophic or hydrologic factors. Considering functional feeding groups, increases in shredders and scrapers and decreases in predators and filterers were detected over time, while collector-gatherers almost did not change in abundance.

Implications of imaginal-size variation over the flight period in stoneflies (Plecoptera)

Abstract In the present study, the decrease in the mean size of specimens over the species flight period in Plecoptera (12 species, 5 families) was analysed, revealing a significant decrease in the adult mean size, for both males and female, in almost all the species without an extended flight-period pattern. Some of the data show that, in addition to temperature, other regulatory factors must govern these variations. Data support the explanation previously proposed for other insect groups that the individuals with appropriate development emerge at the beginning of the flight period or slightly afterwards, when environmental conditions are suitable, whereas individuals with suboptimal size emerge later trying to increase in size but under pressure to emerge during a specific period of the year. Nevertheless, our data suggest that maximum size does not necessarily coincide with the peak flight period (maximum reproductive possibility).

Phenology of Adult Stoneflies (Plecoptera) of the Curone Stream (Northern Apennines, Italy)

ABSTRACT We studied the flight periods of 16 stonefly species from Curone stream (northern Apennines, Italy) and grouped them into four categories according to their flight periods—autumnal (Protonemura salfii and Leuctra major,) autumnal-winter (Leuctra fusca and Leuctra hexacantha,) winter-spring (Leuctra hippopus and Leuctra subalpina,) and spring (Besdolus ravizzarum, Isoperla grammatica, Perla grandis, Perla marginata, Brachyptera risi, Amphinemura sulcicollis, Protonemura intricata, Nemoura hesperiae, Capnioneura nemuroides, and Leuctra handlirschi; probably D. cephalotes can also be added to this category, although no adults were observed). Among the adults, L. fusca was the most abundant species, while C. nemuroides was the rarest. There was partial temporal segregation in the flight periods. In general, the male flight period, at least in some species, occurred slightly in advance of the female flight period.