Nymphal feeding habits of Perla madritensis Rambur 1842 (Plecoptera: Perlidae)

The diet of Perla madritensis, endemic species of the northern half of the Iberian Peninsula, is described for the first time by means of a study carried out in north-western Spain. As other species of the genus Perla, this taxon behaves mainly as predator, with Chironomidae, followed by Baetidae, being the most abundant prey in its gut. Shifts in diet composition were detected in relation to size in this species, with smaller prey being replaced by larger ones such as Simuliidae and Leptophlebiidae when the nymphs become larger.     

Life cycle and nymphal feeding of Besdolus ravizzarum (Plecoptera: Perlodidae), a threatened stonefly

Abstract We have studied some aspects of Besdolus ravizzarum biology in the Apennines. This stonefly has a very localized distribution in southeastern France and northern Italy. This species is considered threatened. For this reason it is especially relevant to improve knowledge about its natural history, previously unknown. Despite the large size of nymphs, this species shows a univoltine life cycle. The growth is slow but uniform from October to April or May when the short flight period occurs. The analysis of the gut contents indicates this species is a predator, feeding mainly on Baetidae and Chironomidae. It is notable that the development of this carnivorous species through cold periods coincides with the season with higher richness and density of potential prey in Apennine streams. Further studies are needed to improve knowledge of the distribution of the species and to start planning effective conservation efforts.     

Life cycle,nymphal feeding and secondary production of Dinocras cephalotes (Plecoptera) in a Mediterranean river

Summary. Some aspects of the life history of a population of Dinocras cephalotes inhabiting a Mediterranean river in Southern Spain were studied over a year (2012–2013). The life cycle of this population seems to be semivoltine, of approximately two years of duration, and with an asynchronous egg hatching period. The comparison of these data with those of an unpublished study carried out in the same population almost a decade before (2004–2005) shows the existence of no differences between years. The nymphal feeding study revealed that the main prey of these organisms are Chironomidae, Psychomyiidae and Baetidae, but some of them, usually the smallest, also had non-animal matter in their guts, mainly detritus, coarse particulate organic matter and algae. So, an onthogenetic shift in feeding was detected. This feeding confirms broadly what was already reported in previous studies in the same and other populations. Finally, and for the first time for this species, the secondary production was estimated. Due to differences in hatching, and so development, among nymphs, annual secondary production was calculated both assuming a CPI of 20 months and a CPI of 14 months. In both cases this value was relatively high, 2854.46 and 4077.80 mg DW m^–2 year^–1, respectively. These results were compared with those of other predators, and particularly with a stonefly predator with a similar life cycle and from a nearby temporal river.     

Life cycle and production of Skwala parallela (Frison) (Plecoptera: Perlodidae) in a Colorado montane stream

The life cycle and production of Skwala parallela, a perlodid stonefly, was investigated in a third-order Colorado montane stream. The species exhibited a univoltine life cycle with a distinct cohort. Small nymphs appeared in May. Rapid growth was exhibited throughout summer and autumn. During winter, growth slowed somewhat but was continuous until April. Maximum density of 34 nymphs/m² occurred in July. Based upon the instantaneous growth method, annual production was 395.3 mg/m² or 3.95 kg/ha dry weight with a P/B ratio of 4.4     

First fossil record of Brachyptera (Plecoptera: Taeniopterygidae) in Eocene Baltic amber

The extant taeniopterygid genus Brachyptera Newport, 1848 is reported from the Eocene Baltic amber for the first time. A new species, Brachyptera dewalti n. sp. (Plecoptera: Taeniopterygidae), is described and illustrated based on a well-preserved female in the amber, distinguished by the presence of three well-developed ocelli, the dark color of antennae, maxillary palps, head, prothorax, and abdominal segments, the CuA vein of forewing with three branches, the nearly rhombus, dark brown postgenital plate, and the four-segmented cerci. It is the fourth taeniopterygid species known from the Baltic amber.     

Contribution to the knowledge of the adult feeding of Nemouroidea stoneflies (Insecta: Plecoptera)

The feeding habits of 17 species of Nemouroidea stoneflies (belonging to the families Nemouridae, Leuctridae and Capniidae) from the north‐western Iberian Peninsula are described and quantified by means of gut content analyses. As a whole, fungi, followed by pollen (both from angiosperm and, in a lesser degree, Pinaceae), leaf fragments (CPOM), detritus and, more punctually, lichens and animal matter are the most common items found in their guts. Nevertheless, variations among species were observed. For a species with a flight period that extends throughout the year, Protonemura globosa, variations in the diet were noticed among seasons, with pollen being more important during the spring and summer period. Together with a few previous studies, the present one reaffirms that feeding is an important aspect of the adult life in males and females of Nemouroidea.     

Designation of a type species for Brachyptera Newport, 1851 (Plecoptera: Taeniopterygidae)

Nemoura trifasciata Pictet, 1832 is designated as type species of Brachyptera Newport, 1851 (Plecoptera: Taeniopterygidae).     

变化光周期对丽斗蟋(Velarifictonus ornatus)若虫发育的影响

为弄清湖南株洲丽斗蟋若虫的季节适应策略,研究了恒定及变化光周期对其若虫发育的调控。结果表明,丽斗蟋若虫发育明显受变化光周期的影响。25℃温度条件下,3个光周期条件下的若虫发育都较慢,羽化也极不整齐,长日条件(LD 16∶8h)、中间日照条件(LD 14∶10h)和短日条件(LD 12∶12h)的若虫发育历期(mean ± SD)分别为(206.2± 44.0)d、(236.6±93.3)d和(230.3±47.4)d,若虫从开始羽化到供试个体全部完成羽化所需时间分别为216、301和156d,经历短日条件的若虫转移至长日条件后能够促进其快速发育,羽化也很整齐,反方向转移则会抑制若虫发育,且羽化也不整齐。30℃温度条件下,恒定长日条件下的若虫发育明显快于短日条件,变化光周期对若虫发育的调控与25℃相类似。变化光周期对若虫发育的影响与光周期的变化方向及低龄若虫感受的光周期类型有关。丽斗蟋若虫复杂的光周期反应模式的生态意义在于调节其生活史与季节同步。     

Life history and production of Agapetus quadratus (Trichoptera: Glossosomatidae) in a temporary, spring-fed stream

1. The life history and trophic basis of production of the caddisfly grazer Agapetus quadratus were studied in the torrent Gorg Blau, a spring‐fed stream on the island of Majorca that dries annually during summer. 2. Quantitative random samples were taken every 2–3 weeks during an annual surficial flow period, from November 2000 to mid‐July 2001. Instars of field‐collected larvae were determined by measurements of head width and pronotum length, and the sex of all pupae was determined to study sexual dimorphism and sex ratio. 3. Stage‐frequency histograms suggested a trivoltine population, with an average cohort time of 4 months. Larval development was asynchronous, with continuous growth and overlapping generations. Recruitment peaks were identified in mid‐November, early March and late June, indicative of winter, spring and summer generations. On average, females were larger than males and the mean sex ratio was 2 : 3 (females : males). Population densities and biomasses derived from the field data were used to calculate production and turnover rate. 4. Annual production of A. quadratus in the torrent Gorg Blau (4.80 g dry mass m^?2 year^?1) was the highest ever reported for the genus, being comparable with that estimated for some insects with rapid development and multiple cohorts. 5. Estimates of production of A. quadratus were combined with foregut content analysis to estimate the fraction of total production derived from the principal food sources: algae and organic detritus. Algae supported a major proportion of the production of this grazer. 6. The low density of predators characteristic of many temporary streams, and the small amplitudes in discharge and temperature during most of the wet period that characterise the spring habitats might allow high levels of grazer production in this particular Mediterranean stream.     

A review of stoneflies of the family Taeniopterygidae (Plecoptera) in Russia and adjacent countries

Twenty-one species of the following eight genera of the family Taeniopterygidae were recorded from Russia and adjacent countries (within the limits of the former USSR): Taeniopteryx (4 species), Brachyptera (7), Kyphopteryx (2), Mesyatsia (2), Oempoteryx (1), Rhabdiopteryx (3), Strophopteryx (1), and Taenionema (1). All the species belong to the Palaearctic complex, which is subdivided into the following groups: transpalearctic (1 species), western-Palaearctic (5), Ponto-Caucasian (3: 2 endemics of the Caucasus and 1 species distributed in the Caucasus and Anatolia). Middle-Asian (3), eastern-Palaearctic (1), and Palearchaearctic (1).     

温度对蟋蟀若虫生长发育的影响

澳洲黑蟋蟀Teleogryllus commodusWalker若虫在22℃下,有9个龄期,在28℃下,只有8个龄期。若虫在22℃和28℃的平均历期分别是159d和79d,并且若虫胸部和腹部相对于头部的生长速率在低温条件下均小于高温条件下的若虫。     

变化光周期对丽斗蟋(Velarifictonus ornatus)若虫发育的影响

为弄清湖南株洲丽斗蟋若虫的季节适应策略,研究了恒定及变化光周期对其若虫发育的调控.结果表明,丽斗蟋若虫发育明显受变化光周期的影响.25℃温度条件下,3个光周期条件下的若虫发育都较慢,羽化也极不整齐,长日条件(LD 16:8h)、中间日照条件(LD 14:10h)和短日条件(LD 12:12h)的若虫发育历期(mean±SD)分别为(206.2±44.0)d、(236.6±93.3)d和(230.3±47.4)d,若虫从开始羽化到供试个体全部完成羽化所需时间分别为216、301和156d,经历短日条件的若虫转移至长日条件后能够促进其快速发育,羽化也很整齐,反方向转移则会抑制若虫发育,且羽化也不整齐.30℃温度条件下,恒定长日条件下的若虫发育明显快于短日条件,变化光周期对若虫发育的调控与25℃相类似.变化光周期对若虫发育的影响与光周期的变化方向及低龄若虫感受的光周期类型有关.丽斗蟋若虫复杂的光周期反应模式的生态意义在于调节其生活史与季节同步.     

Stoneflies (Plecoptera) in the diet of brook trout (Salvelinus fontinalis Mitchell) in Libby Creek,Wyoming, USA

The stonefly component of a naturally reproducing population of brook trout ( Salvelinus fontinalis) was studied by analyzing 216 stomach pump samples collected between May 15 and August 10, 1991 and 1992, from Libby Creek, an alpine stream in the Medicine Bow National Forest in Wyoming. Stoneflies constituted 10.3% of the total items recovered and were the second most abundant order in the samples. Nineteen species of Plecoptera representing five families were identified. Approximately 43% of all stoneflies were Sweltsa lamba; the next most prevalent species was Zapada haysi (12%). The other prevalent insect orders in the samples were Diptera (57.2%), Ephemeroptera (8.4%) and Trichoptera (6.1%). Terrestrial Coleoptera, Hymenoptera, and Hemiptera were most common in July and August. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ohio USA stoneflies (Insecta, Plecoptera): species richness estimation, distribution of functional niche traits, drainage affiliations, and relationships to other states

Ohio is an eastern USA state that historically was >70% covered in upland and mixed coniferous forest; about 60% of it glaciated by the Wisconsinan glacial episode. Its stonefly fauna has been studied in piecemeal fashion until now. The assemblage of Ohio stoneflies was assessed from over 4,000 records accumulated from 18 institutions, new collections, and trusted literature sources. Species richness totaled 102 with estimators Chao2 and ICE Mean predicting 105.6 and 106.4, respectively. Singletons and doubletons totaled 18 species. All North American families were represented with Perlidae accounted for the highest number of species at 34. The family Peltoperlidae contributed a single species. Most species had univoltine-fast life cycles with the vast majority emerging in summer, although there was a significant component of winter stoneflies. Nine United States Geological Survey hierarchical drainage units level 6 (HUC6) were used to stratify specimen data. Species richness was significantly related to the number of unique HUC6 locations, but there was no relationship with HUC6 drainage area. A nonparametric multidimensional scaling analysis found that larger HUC6s in the western part of the state had similar assemblages with lower species richness that were found to align with more savanna and wetland habitat. Other drainages having richer assemblages were aligned with upland deciduous and mixed coniferous forests of the east and south where slopes were higher. The Ohio assemblage was most similar to the well-studied fauna of Indiana (88 spp.) and Kentucky (108 spp.), two neighboring states. Many rare species and several high quality stream reaches should be considered for greater protection.     

Interspecific and intraspecific variations in egg hatching for British populations of Taeniopteryx nebulosa and Brachyptera risi (Plecoptera: Taeniopterygidae)

Adults were obtained from three populations of Taeniopteryx nebulosa and four populations of Brachyptera risi ; their eggs were incubated at seven constant temperatures (range 3.8–22.1°C). There were interspecific, but not intraspecific, differences in adult life-span, mean number of eggs laid per female, hatching success and egg incubation periods. The optimum temperature for hatching success and the range over which at least 50% of the eggs hatched were lower for T. nebulosa (6.5°C, 2.7–15.0°C) than for B. risi (9.0°C, 5.1–15.8°C). No eggs hatched at 22.1°C. The relationship between incubation period (d days) and water temperature (T°C) was given by; d = 326.4 T^−1.015 for T. nebulosa , d = 824.0 T^−0.739 for B. risi . Both equations successfully predicted incubation periods for eggs placed in a stream.
Hatching success and incubation periods were similar to those already published for a Norwegian population of T. nebulosa . The lack of significant intraspecific variation suggests that the genotypes associated with the variables examined in this study have remained remarkably stable in these two species in spite of the geographical isolation of their different populations.     

蒙古寒蝉成、若虫触角形态及若虫龄期判别研究（半翅目：蝉科）

对蒙古寒蝉若虫与成虫的触角感器进行了研究,并结合不同龄期若虫触角的形态特征,采用Dyar法则与“头宽—龄期”的回归曲线验证,初步断定蒙古寒蝉若虫具有4个龄期。不同龄期若虫与成虫的触角形态差异显著,触角感器的种类、数量和分布也明显不同,其差异或与若虫和成虫的生态位不同密切相关。     

The effects of aggregation on survival and growth rate in the wood‐feeding cockroach Panesthia angustipennis spadica (Blaberidae)

The wood‐feeding cockroach Panesthia angustipennis spadica Shiraki (Blaberidae) is a gregarious species, and its groups containing both nymphs and adults have often been observed in the field. To clarify the effects of aggregation with a parent and siblings on nymphal development in P. angustipennis spadica, we raised nymphs of this species in the laboratory under the following three experimental categories: (a) aggregate with a female adult; (b) aggregate without a female adult; and (c) solitary. Survival rates did not significantly differ among the three categories. Unexpectedly, our results clearly showed that nymphs raised in aggregates with a female adult were smaller, lighter, and reached a lower instar than those raised without a female adult. These results indicate that the presence of a female adult does not positively affect nymphal development; i.e. there may be no direct parental care in this species as indicated by previous studies. Moreover, solitary nymphs grew faster and larger than nymphs in aggregates, showing that the aggregation with siblings also has no positive effect on nymphal development. Thus, it seems likely that external factors, e.g. predation and environmental conditions, may drive aggregating behavior in P. angustipennis spadica.     

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.     

Filters and templates: stonefly (Plecoptera) richness in Ouachita Mountains streams, U.S.A.

1.  We collected adult stoneflies periodically over a 1-year period at 38 sites in two headwater catchments in the Ouachita Mountains, Arkansas, U.S.A. The 43 species collected were a subset of the Ozark-Ouachita fauna and the much larger fauna of the eastern U.S.A. We estimated 78–91% species coverage in the two catchments using jackknife extrapolation of species richness from our survey.
2.  Many streams, especially small ones, lacked surface water for months, but others, both small and large, flowed permanently.
3.  Using published regional presence–absence and coarse ecological data in a discriminant function analysis (DFA), we identified stream size (negative) and regional frequency of occurrence (positive) as predictors of presence in these headwater catchments. For the combined catchments, the extrapolated richness (51 spp.) was similar to an estimate (48 spp.) based on predicted absences from DFA and the Ouachita provincial total of known stonefly species (57 spp.).
4.  Local species richness (1–27 spp. per site) was correlated strongly with stream size (catchment area) but was independent of stream drying. Generic richness was correlated negatively with stream drying and positively, but less strongly, with stream size.
5.  Regionally endemic stoneflies dominated in drying streams, and widely distributed species dominated in more permanent streams. The composition of stonefly assemblages was associated with regional factors (species pools, regional abundance, evolution of tolerant endemic species, regional climate) and local factors (drying, stream size).