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Exp Appl Acarol (2013) 61:161172 DOI 10.1007/s10493-013-9687-5
Tobias Pngstl
Received: 20 September 2012 / Accepted: 11 March 2013 / Published online: 21 March 2013 Springer Science+Business Media Dordrecht 2013
Abstract The population dynamics of the three intertidal oribatid species, Alismobates inexpectatus, Fortuynia atlantica and Carinozetes bermudensis, have been studied on the archipelago of Bermuda over the course of a year. All three species are univoltine, showing a clear seasonal demographic pattern, with reproduction from spring to late autumn and a complete standstill of egg production in winter. A seasonal shift in sex ratio could also be observed in all three species and is supposed to be based on sex-dependent mortality. The subtropical climate of Bermuda allows longer reproductive periods than shown in other intertidal or edaphic temperate species and temperature is supposed to be the main factor inuencing the demography of these intertidal dwelling mites. Although all three Bermudian species exhibit the same basic seasonal demographic pattern, there are slight temporal shifts in population dynamics, presumably caused by local microclimatic differences among the populations. Larviparity, shown in other littoral oribatid mites, is clearly absent in the present species.
Keywords Reproduction Sex ratio Juveniles Eggs Seasonality
Introduction
The majority of oribatid mites is represented by terrestrial taxa and only few have colonized aquatic and semiaquatic habitats. Certain oribatid taxa have also managed to conquer the marine environment but are restricted to littoral zones. Over 90 % of these intertidal oribatid mites belong to the superfamily of Ameronothroidea containing the families Ameronothridae, Fortuyniidae and Selenoribatidae (Proches and Marshall 2001). These families show distinct global distribution patterns with the Ameronothridae conned to polar and subpolar regions and the Fortuyniidae and Selenoribatidae distributed only in tropic and subtropic areas (e.g. Schuster 1989). Although these taxa have likewise
T. Pngstl (&)
Bermuda Institute of Ocean Sciences Inc. (BIOS), 17 Biological Lane, St. Georges GE 01, Bermuda e-mail: [email protected]
T. Pngstl
Institute of Zoology, Karl-Franzens University Graz, Universitatsplatz 2, 8010 Graz, Austria
Population dynamics of intertidal oribatid mites (Acari: Cryptostigmata) from the subtropical archipelago of Bermuda
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successfully colonized the littoral habitat, they are occurring in different temperature regimes. As temperature is an important factor inuencing growth rates, developmental times, hence life histories and population...