Allopatric Congener Research Articles

Detection of conspecific and heterospecific alarm signals by juvenile pumpkinseed under weak acidic conditions

Under neutral (pH 7·0) conditions, juvenile pumpkinseed Lepomis gibbosus exhibited significant antipredator responses, of similar intensities, to the chemical alarm cues of conspecifics, an allopatric congener the green sunfish Lepomis cyanellus and the artificial alarm cue of a sympatric prey guild member (Cyprinidae, hypoxanthine‐3‐N‐oxide). Under weakly acidic conditions (pH 6·0), however, no increase in antipredator behaviour was seen in response to hypoxanthine‐3‐N‐oxide and a quantitatively weaker response was found in response to conspecific and congener cues, suggesting that the use of chemical alarm cues by some prey fishes may be impaired by acid precipitation.

Geographic isolation and evolution of Mediterranean endemic Cyclamen : insights from chloroplast trn L (UAA) intron sequence variation

In this study we construct a phylogenetic hypothesis for the relatedness among disjunct subspecies of Cyclamen repandum and its two allopatric congeners, C. creticum and C. balearicum in order to examine the evolutionary divergence of currently isolated populations across the western Mediterranean. The most parsimonious phylogenetic tree obtained from sequencing the cpDNA trnL (UAA) intron suggests a major phylogeographic divide in southern Greece between two clades. The first clade comprises samples of C. repandum subsp. peloponnesiacum (from the Peloponnese) and C. creticum (from Crete). The second comprises samples of C. repandum subsp. repandum (from Croatia, Italy, southern France, Corsica, Sardinia and Sicily), C. repandum subsp. rhodense (from Rhodes and Kos) and C. balearicum (from the Balearic Islands and southern France). These data suggest that C. creticum has evolved in allopatry from C. repandum subsp. peloponnesiacum and that C. balearicum and C. repandum ssp. rhodense have diverged from C. repandum subsp. repandum at its western and eastern distribution limits. At one small site on Corsica, a population of C. repandum may have introgressed with relictual populations of C. balearicum. These divergence patterns illustrate how a phylogenetic perspective can be used to better understand the evolution of endemism in the Mediterranean flora.

CONSUMPTION OF AMPHIPODS BY THE NEW ZEALAND LAND SNAIL WAINUIA URNULA (PULMONATA: RHYTIDIDAE)

An unusual carnivorous diet was documented for the rhytidid snail Wainuia urnula urnula (Pfeiffer) from the southern North Island, New Zealand. Eighty-two percent of 315 samples of faeces or gut contents contained remains of landhoppers (Crustacea: Amphipoda). Earthworms (Oligochaeta) were the second most common food type identified, but occurred in only 4 percent of samples. In the laboratory, W. urnula urnula captured landhoppers by rapidly everting the TVU-section odontophore beneath the prey and immediately drawing it into the mouth in a single action. Diet samples from the allopatric congeners W. edwardi (Suter) (n 5 51) and W. clarki Powell (n 5 7) contained no remains of landhoppers, and these snails did not eat landhoppers in the laboratory. The diet of these species was dominated by earthworms. The subspecies W. u. nasuta ate both earthworms and amphipods with similar frequency (n 5 40). Individual teeth on the radula of W. urnula urnula had a simple blade-like cusp like other Wainuia species, but there were fewer teeth per row and fewer rows on the whole radula than in other species. W. u. nasuta had a similar number of rows of teeth to W. clarki and W. edwardi, but the number of teeth per row was intermediate between these species and W. u. urnula. Records of pulmonate species preying on arthropods are rare, yet in the case of W. urnula this specialization has been accompanied by minimal morphological change.

Behavioural responses by hatchling racers (Coluber constrictor) from two geographically distinct populations to chemical stimuli from potential prey and predators

AbstractIn experiments on responses to chemical food stimuli by previously unfed hatchlings from widely separated populations of the colubrid snake Coluber constrictor in the United States, strong responses were elicited by items important in the local diet. These differed between populations, suggesting that response has been adjusted to local diet by natural selection. Coluber constrictor priapus from South Carolina tongue-flicked at elevated rates to cues from lizards, snakes, and frogs, and bit only in response to a preferred lizard prey. They responded more strongly to the sympatric lizard Anolis carolinensis than to A. sagrei, an allopatric congener. Strong response to cues from the ophidiophagous snake Lampropeltis triangulum might reflect motivation for predator avoidance or for feeding, depending on relative snake sizes. Coluber constrictor mormon, for which insects and mammals are the most important foods, responded most strongly to stimuli from sympatric insects, mammals, and a lizard, as well as a bird.

Microhabitat of the Narrow Florida Scrub Endemic Dicerandra christmanii, with Comparisons to Its Congener D. Frutescens

MENGES, E.S., PJ. MCINTYRE, M.S. FINER, E. Goss, AND R. YAHR (Archbold Biological Station, PO Box 2057, Lake Placid, FL 33870). Microhabitat of the narrow Florida scrub endemic Dicerandra christmanii, with comparisons to its congener D. frutescens. J. Torrey Bot. Soc. 126:24-31. 1999.-We characterized the microhabitats of the endemic Florida scrub plant Dicerandra christmanii in comparison to random points in the same abandoned sand road and random points in adjoining mature oak scrub lacking plants. We also compared microhabitat preferences of D. christmanii to its endemic, allopatric congener D. frutescens, a plant with a similar life history growing in similar habitats. Plants of D. christmanii occur in microhabitats with significantly more open canopies, shorter shrubs, and lower litter cover and depth than random points in the scrub. Random points in the abandoned road had intermediate microhabitats. D. christmanii had similar quadrat occupancy patterns across gradients of litter depth and cover as its congener. However, it occurred less often than D. frutescens under closed canopies and near tall shrubs. The microhabitat preferred by D. christmanii (canopy cover < 60%, shrub height < 3m, litter cover < 80%, litter depth < 2 cm) is absent in mature oak scrub unburned for several decades. Suitable microhabitat can probably be provided by periodic prescribed fire or other disturbances that temporarily remove shrub cover and litter, although the response of D. christmanii to these treatments has not been studied.

Aulohalaelurus kanakorum n.sp., a new species of Catshark (Carcharhiniformes, Scyliorhinidae, Atelomycterinae) from New Caledonia

A new catshark, Aulohahaelurus kanakorum n.sp., is described from an adult male collected from off south-western New Caledonia. It is the second species in the genus Aulohalaelurus, previously restricted to western Australia. The new species is distinct from its allopatric congener, Aulohalaelurus labiosus (Waite, 1905), mainly by colour pattern, longer interdorsal space, pelvic-anal distance, shorter prepelvic length, morphology of dermal denticles and higher number of diplospondylous vertebrae. A neotype is also designated for A. labiosus (Waite, 1905).