Coexistence in a guild of filter feeding caddis larvae: do different instars act as different species?

Summary Guild structure and coexistence of filter feeding caddis larvae was studied in three lake-outlet streams in northern Finland. Natural stones were used as sampling units, and for each stone measurements of six microhabitat variables were taken. Species and species instar relationships in the multivariate microhabitat space were analyzed by a method based on Principal Components Analysis. Seven species of filtering caddis larvae were found at the study sites, but detailed analysis was restricted to the four most abundant ones (Polycentropus flavomaculatus, Hydropsyche angustipennis, H. pellucidula, H. saxonica). P. flavomaculatus was the microhabitat generalist of the guild, whereas all the hydropsychids were narrowly specialized in at least one larval instar. In all species, different instars utilized the microhabitat somewhat differentially. Moss content and Froude number were significantly different between instar microhabitats in all comparisons. Ontogenetic niche changes not only separated species instars from each other, but also profoundly changed the biotic as well as abiotic environment of the species at different phases of larval development. This may have important effects on the dynamics of interacting species and, consequently, on the guild structure. While some of the more classical models of coexistence may also be relevant for understanding coexistence in this guild of sessile stream insects, ontogenetic niche changes clearly need to be taken into consideration in future studies of guild structure and species interactions of filter feeding caddisfly larvae.     

Neophylax kolodskii (Trichoptera: Uenoidae), A New Species from the Great Smoky Mountains National Park,U.S.A.

Neophylax kolodskii sp. n. from Great Smoky Mountains National Park is described and illustrated from adult specimens.     

New records of polycentropodid caddisflies from Korea (Insecta: Trichoptera)

Four species of the family Polycentropodidae –Plectrocnemia baculifera, P. kusnezovi, Paranyctiophylax hjangsanchonus and Polyplectropus nocturnus– are recorded from Korea. Polyplectropus nocturnus is newly recorded from the Korean peninsula. The other three species are recorded from the Republic of Korea for the first time.     

Sub-lethal effects of disturbance on a predatory net-spinning caddisfly

1. The sub-lethal effects of hydrologic disturbances on stream invertebrates are poorly understood, but integral to some models of how disturbances influence population and community dynamics. Carnivorous larvae of a net-spinning caddisfly, Plectrocnemia conspersa , have a strong predatory impact in some streams. Their silken nets, however, are vulnerable to high flow disturbance and the consequent destruction of nets could reduce predatory impacts and have life history consequences.
2. In a laboratory experiment, we manipulated the frequency of disturbances that destroyed the nets of P. conspersa , in the presence and absence of potential prey. Animals were housed individually and each trial lasted 8 days. We estimated net size, cumulative mass of silk produced, net allocation (net mass expressed as a proportion of body mass), per capita prey consumption and growth or mass loss of larvae.
3. In the absence of prey, increased disturbance frequency was accompanied by increased loss of body mass, a reduction of net size and an increase in the cumulative mass of silk produced. At the highest disturbance frequency, larvae eventually gave up producing nets. The ratio of net mass to body mass decreased with increasing disturbance, suggesting a trade-off in the allocation of resources, with a decreasing proportion of resources available for foraging. In the presence of prey, increased disturbance frequency was accompanied by a reduction in per capita prey consumption. Although foraging success offset the costs of silk production, growth rate decreased with increasing disturbance and could eventually lead to reduced body size and fecundity of adults.
4. These sub-lethal effects suggest that hydrologic disturbances could impose metabolic costs and reduce foraging efficiency of this predator. Thus, disturbances may reduce predator impact on prey populations and reduce predator population size without any direct mortality or loss of individuals.     

Twenty-one new Polyplectropus species from New Caledonia (Trichoptera: Polycentropodidae)

Twenty-one new Polycentropodidae (Trichoptera) species are described: Polyplectropus aberrus, P. dorsospinus, P. nodyg, P. yndog, P. clavus, P. nathalae, P. millei, P. christinae, P. koueus, P. viklundi, P. hovmoelleri, P. aoupiniensis, P. tenerus, P. angustus, P. curvispinus, P. caledonia, P. piroguensis, P. triangulatus, P. pernodensis, P. taoensis, and P. papei spp. novae, representing the first species records of this family from New Caledonia. A key to males of the New Caledonian Polycentropodidae is provided, and distribution maps are presented for all species.     

中国新纪录——隐刺多距石蛾属及一新种记述(毛翅目,多距石蛾科)

记述多距石蛾科中国1新纪录属,隐刺多距石蛾属Pahamunaya Schmid,1958,同时描述1新种,中华隐刺多距石蛾Pahamunaya sinensis sp.nov..模式标本保存在南京农业大学昆虫标本馆.中华隐刺多距石蛾,新种Pahamunaya sinensis sp.nov.(图1～5)本种与越南种Pahamunaya directmis Malicky,1995雄性外生殖器的主要区别特征如下：：新种第9节下附肢背部具长度约相等的2个分枝,前分枝棒槌状并多毛,后分枝扁叶状,亚长三角形,其外侧缘具2个耳状突起,内侧缘具1排细刚毛,基部的2根极为粗长;而后者下附肢背部的前分枝短小,末端三叉状,后分枝简单,腹面观呈弧状突,无粗刚毛.正模♂,广东省五华县(23°49′N,115°22′E;海拔431 m),七目嶂,大田镇东北9km,水坝上游600 m无名溪西支流,2004-05-30,周欣采.副模：1 ♂,广东省五华县(23.83°N,115.40°E;海拔426 m),七目嶂,大田镇东北9km,水坝上游300 m无名溪东支流,2004-05-30,杨莲芳、J.C.Morse采;1♀,广东省肇庆市(23.16°N,112.53°E;海拔132 m),鼎湖山保护区东沟,2004-05-24,杨莲芳、周欣采;1♂,广西上思县(21.89°N,107.91°E;海拔392m),十万大山保护区石头河二级支流,距保护区入口西南3.4km,2004-06-06,杨莲芳、C.J.Gerad采;l ♂,浙江天目山(30.4°N,119.5°E;海拔500 m),后山门,1998-07-03,吴鸿采;l♂,浙江临安天目山山门藻溪(30.32°N,119.44°E;海拔293m),2011-07-26,孙长海采.     

Isolation of polymorphic microsatellite loci in the net‐spinning caddisfly,Polycentropus flavomaculatus (Polycentropodidae)

We have isolated eight polymorphic loci for the caddisfly, Polycentropus flavomaculatus. The application of these markers will allow us to define the genetic population structure of this species and, with complementary ecological work, will enable quantification of its dispersal ability and colonization potential.     

Twenty-four new species of Polycentropus (Trichoptera, Polycentropodidae) from Brazil

Twenty-four new species of the caddisfly genus Polycentropus (Insecta: Trichoptera: Polycentropodidae) occurring in Brazil are diagnosed, described, and the male genitalia of each are illustrated. Eighteen of the new species are placed in the Polycentropus jorgenseni species complex of the Polycentropus gertschi group of New World Polycentropussensu lato. Furthermore, 6 new species within the Polycentropus gertschi group (Polycentropus ancistrussp. n., Polycentropus boraceiasp. n., Polycentropus cariocasp. n., Polycentropus froehlichisp. n., Polycentropus galharadasp. n., and Polycentropus graciosasp. n.) are placed in an informal diagnostic cluster of species with Polycentropus urubici Holzenthal and Almeida. Ten of the other Polycentropus gertschi group species form a second cluster of diagnostically similar species, the Polycentropus soniae cluster (Polycentropus caaetesp. n., Polycentropus carolaesp. n., Polycentropus cheliceratussp. n., Polycentropus fluminensissp. n., Polycentropus itatiaiasp. n., Polycentropus minerosp. n., Polycentropus santateresaesp. n., Polycentropus soniaesp. n., Polycentropus tripuisp. n., and Polycentropus virginiaesp. n.). Two of the remaining 8 new species are included in the Polycentropus jorgenseni species complex (Polycentropus cipoensissp. n. and Polycentropus verruculussp. n.), while the remaining 6 are unique and cannot be placed in one of the groups at this time (Polycentropus acinaciformissp. n., Polycentropus amphirhamphussp. n., Polycentropus cachoeirasp. n., Polycentropus inusitatussp. n., Polycentropus paprockiisp. n. and Polycentropus rosalysaesp. n.).