Insect emergence from a shallow southern West German lake, with special reference to the parasitic host-associated water mite larvae

Abstract

Insect emergence was studied with floating box traps in the littoral of Lake Mindelsee from July 1st until September 30th, 1984. The material was collected every 48 h. Out of the total catch of 6897 specimens per m 2 , 75.1% belonged to the Chironomidae, 4,9% to the Chaoboridae, 15,4% to the Ephemeroptera and 3,2% to the Trichoptera.Endochironomus sp., Lauterborniella agrayloides, Polypedilum pullum (Chironomidae) and Oocetis testacea (Trichoptera) are reported for the first time from Lake Mindelsee.The seasonal course of the total emergence showed two distinct peaks: one at the end of July, the other at the beginning of September.Diurnal emergence was studied on two occasions, in July and in August. Most of the insects emerged during dusk and dawn.Species composition and degree of water mite infection of the collected nematocerans were studied. Host range and specific attachment sites of the different water mite taxa could only be established on the genus or family-level, with the exception of the most common water mite species Hydrodroma despiciens. In addition to its main host Chaoborusflavicans, this mite species infested 16 chironomid species with Corynoneura sp., Cryptocladopelma viridula, Pseudochironomusprasinatus and Tanytarsus lactescens as new records. The larvae of Hydrodroma despiciens were attached almost exclusively to the thorax of the imagines. Chaoborusflavicans, and within the Chironomidae Procladius sp. of the subfamily Tanypodinae, showed the highest average mite load. Species of the subfamily Chironominae were also heavily infested (e.g. Microtendipes sp., infestation rate 76% with a maximum mite load of 18). Within the representatives of the subfamily Orthocladiinae however, only low infestation rates occurred with maximum one larva per host.Finally, problems like the synchronization of the life-cycles of hosts and parasites and strategies of coexistence between the different water mite taxa parasitizing one host are discussed.

Larval parasitism of spring-dwelling alpine water mites (Hydrachnidia, Acari): a study with particular reference to chironomid hosts

“…Other habitats also exhibit a higher overall prevalence of parasitized chironomids than in the present study (e.g., stream: 16.9%, P. Martin, unpublished data, lake littoral: 14-23%, Smukalla and Meyer 1988). However, as in the other studies referred to, also in Berchtesgaden, at least during some seasons, almost the complete population of some species could be found parasitized by mites.…”

Tracking Diet Preferences of Bats Using Stable Isotope and Fatty Acid Signatures of Faeces

“…During the study period the average air temperature gradually increased (from 14.7°C to 24.7°C) likely resulting in changes in relative abundance of certain prey species or the general composition of the insect community the bats fed on (e.g. [46] , [47] ). Also the stable isotope and fatty acid signatures of the insects may have changed seasonally (e.g.…”

Seasonal bat activity related to insect emergence at three temperate lakes

“…The Pipistrellus species accounted for most of the activity in all the lakes, and so we do not expect the species composition to be responsible for these activity differences. The nocturnal pattern of bat activity seemed to follow the usual bimodal peaks of insect emergence at dawn and dusk (e.g., Smukalla & Meyer, 1988;Rydell, Entwistle, & Racey, 1996) in the spring/ summer for Lake Constance, and in the summer for Siechenweiher. A possible explanation for the absence of a specific pattern in the autumn could be the low insect availability that might drive bats to search longer for food, or individuals might fly at different hours and places (Swift & Racey, 1983).…”

“…depth 12 m), smaller (1.02 km 2 ), mesotrophic to eutrophic lake, included in a nature reserve. We sampled in the southern, steeper littoral zone which is bordered by a hill forested mainly with beech trees (Smukalla & Meyer, ). Siechenweiher (47 o 41′47.33″N, 9 o 16′.54.09″E) is a shallow (max.…”