A polyphenism discovered to consist of five discrete morphotypes shows that extreme diversification is possible within single species.
The temperature dependence of semilunar and diurnal eclosion rhythms in the intertidal midge Clunio mariuus (Diptera, Chironomidae). On Helgoland (North Sea), the imagines of Clunio emerge during two seasonal periods (late spring and summer) from water temperatures of 8°-18 °C. The temperature dependence of the known semilunar eclosion rhythm of Clunio (correlated in nature with the spring tides every 14-15 days) was tested in the laboratory. Between 15 ° and 23 °C the semilunar eclosion maxima varied by only one day within the artifical 15-day zeitgebercycle, below 15 °C they were delayed up to 8 days at 8 °C. However, the days of pupation were approximately independent of the temperature level. One can conclude the existence of a temperature-independent physiological switch inducing the pupation only within a few days of the semilunar zeitgeber-cycle. Moreover, a semilunar synchronized differentiation of the imaginal discs already starts in the preceding larval instal indicating an additional physiological switch. A model is suggested in which the semilunar eclosiou rhythm and its relatively slight temperature dependence is explained by the action of two physiological switches which are coupled with the endogenous temperature-compensated lunar timing mechanism on the same days of the 15-day zeitgeber-cycle. In the laboratory, the diurnal eclosion and its underlying circadian timing mechanism (correlated on Helgoland with the time of spring low water in the late afternoon) also proved to be temperature independent between 12 ° and 20 °C. A comparison of field and laboratory data showed very similar results at temperatures around 18 °C (summer swarming period). In contrast, the midges emerged on all days of the semimonthly cycle of springs and neaps during the spring swarming period. This lack of semilunar synchronization may be the consequence of fluctuating temperatures during the larval and pupal development in spring time due to a general rise in the water temperature (4~-8 °C) and to short temperature rises up to 18 °C during exposure of the intertidal habitat at about low tide. Since some higher parts of the Clunio habitat suitable for egg deposition are exposed on almost every day of the semimonthly cycle, even such animals that undergo lunar unsynchronized metamorphosis can reproduce within the short imaginal life duration (ca 2 h) if they emerge just about the time of low water. In correspondence with the daily delay in the times of low water by about 50 min, the diurnal eclosion rhythm was in fact modified with the tides during the spring period resulting in shifts of the diurnal eclosion time of up to 12 hours within the semimonthly cycle of springs and neaps. EINLEITUNG
Nematodes of figs and fig wasps have received limited attention in Africa since their discovery in 1973. Sixteen of the 25 species of native South African figs were sampled for nematode associates using molecular barcoding with three loci (SSU, LSU D2-D3 and mtCOI) and fourteen (93%) were positive for at least one nematode species. Thirty-three putative species of nematodes were identified and classified according to the loci that were amplified and successfully sequenced. Fourteen putative nematode species were classified as Aphelenchoididae, of which nine were identified as Ficophagus from four species of Ficus from the section Galoglychia (i.e., five ex F. burkei including one shared with F. natalensis, one ex F. glumosa, one ex F. lutea, and one ex F. stuhlmannii) and one species ex F. sur from the section Sycomorus. In addition, there were four nematode species classified as Schistonchus s.s. from section Galoglychia figs (i.e., one ex F. burkei, two ex F. trichopoda, and one ex F. glumosa). There was also one species of Bursaphelenchus nematode recovered from F. sur from the section Sycomorus. Sixteen putative nematode species were classified as Diplogastridae, of which eight occurred in two clades of what is currently called Parasitodiplogaster with one (P. salicifoliae) being recovered from two Ficus species in the section Urostigma (F. salicifolia and F. ingens) and seven diplogastrids being associated with six species of Ficus from the section Galoglychia (i.e., two ex F. burkei including P. sycophilon, one ex F. stuhlmannii, one ex F. burtt-davyi, one ex F. trichopoda, one ex F. abutilifolia and one ex F. sansibarica). Three Acrostichus spp., a Teratodiplogaster and a Pristionchus species were recovered from F. sur and two Teratodiplogaster spp. and Pristionchus sycomori were recovered from F. sycomorus with both Ficus species belonging to the subgenus and section Sycomorus. The identities of the previously described T. martini and Parasitodiplogaster doliostoma (= Pristionchus sp. 35) are discussed. Lastly, there was a panagrolaimid identified from F. petersii.
Breeding experiments with a temperate zone population of the marine insect Clunio marinus (stock Helgoland-North Sea from 54° N) demonstrated an onset of larval diapause under combined short day and low temperature conditions only (examined LD 8:16 with 7 or 10°C resp.). Long photoperiods (LD 16:8) at 7-10° C or higher temperatures in shorter photoperiods completely prevented any dormancy response. The diapausing larvae were still locomotory active and fed in their benthic environment; their metamorphosis, however, stopped during a specific stage of the early imaginal disc formation in the last instar. In the experiments, the diapause was maintained up to 5.5 months and longer. In nature, the termination may be mainly controlled by temperature rises during low tide and fine weather under long day conditions, at Helgoland generally in late April or early May. The dormancy response can be classified as a larval oligopause (sensu H.J. Müller) of a potentially multivoltine species. It is supposed that this kind of diapause control is more widely distributed in aquatic chironomids.
Both the male and the female klipspringer scent-mark their ranges. A pair of pre-orbital glands below the eyes produces the scent. The secretion is a sticky, substance that is deposited on a suitable twig. Klipspringer scent marks were surveyed in a specific klipspringer range in the Kruger National Park with the use of a strip transect method. The results showed that klipspringer in the Kruger National Park scent-mark more frequently on the boundaries of their ranges and also more on those sides where there is another resident klipspringer group.
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