ARACHNOLOGICAL EVIDENCE FOR GLACIAL REFUGIA IN THE BAVARIAN ALPS
MUSTER C.: Arachnological evidence for glacial refugia in the Bavarian Alps. In GAJDOS P., PEKAR S. (eds): Proceedings of the 18th European Colloquium of Arachnology, Stara Lesna, 1999. Ekologia (Bratislava), Vol. 19, Supplement 3/2000, p. 181-192. According to geomorphological conclusions some regions of the Bavarian Alps remained free of ice during the Pleistocene glaciations. The current concepts of phytogeography acknowledge plant survival during cryocratic periods in Bavarian massifs de refuge as well as on the nunatak system. Hitherto in zoogeography, little proof has been offered in support of these assumptions. According to recent investigations the distribution areas of the arachnids Cryphoeca lichenum nigerrima (Hahniidae) and Megabunus lesserti (Phalangiidae) suggest continuous inhabitation of Bavarian refugia since interglacial times. Especially in the Ammergau refugium the persistance of animal life during the last glaciation could be confirmed.
Divergence and diversity: lessons from an arctic–alpine distribution (Pardosa saltuaria group, Lycosidae)
The relationship of interpopulation genetic divergence and within‐population diversity has been studied for many temperate species in Europe, but not for the cold‐adapted fauna. Here we present the first European‐wide phylogeographical study of an arctic–alpine distribution in invertebrates, focusing on wolf spiders of the Pardosa saltuaria group. One hundred twenty‐seven (127) specimens from 14 populations were examined. Within Europe, these populations were distributed among six high mountain ranges and Scandinavia. We sequenced the whole 921 base pair mitochondrial (mt) ND1 gene. The resulting 55 unique haplotypes form three monophyletic phylogroups of deep divergence: a Pyrenean, a Balkan and a ‘northern’ clade. Genetic distances (3.6–4.0%) between the major clades indicate that the arctic–alpine range disjunction was initiated by vicariance events, which precede the four major Alpine glaciations. However, low divergence and incomplete lineage sorting within the ‘northern clade’ suggest a late Pleistocene separation of the Alpine, Scandinavian, Carpathian and Sudetian populations. Thus, we provide evidence for a multiglacial origin of arctic–alpine distributions in Europe, i.e. the current disjunction results from range fragmentation in several glacial cycles. The pattern of genetic diversity within populations seems predominantly determined by historical factors, but is modified by contemporary aspects. Overall, diversity and divergence are negatively correlated. We suggest that low diversity values might result from (i) ancient bottlenecking during warm interglacial periods, as seen in the Pyrenees and Balkans; (ii) recent bottlenecking in small modern areas, as seen in the Giant Mountains and Bohemian Forest; and (iii) dispersal bottlenecking in northern Scandinavia.
Morpho-biometric Relationship, Relative Condition Factor and Meat Yield of Distant Scallop Bractechlamys vexillum (Reeve, 1853) in Asid Gulf, Philippines
Understanding the relationships of morphometric and biometric characters of a species allows the prediction of one trait from the other and generate a measure of relative condition. These relationships were studied for the Distant scallop Bratechlamys vexillum (Reeve, 1853) in Asid Gulf. Representative samples collected during the dry season (May 2018, n = 99) and wet season (September 2018, n = 100) were used to analyse these relationships through models of simple linear and power regression analyses, revealing allometric growth patterns. For both periods, it was revealed that shell width (SW) is a slightly better predictor than the height (SH) for total weight (TW) (R2 = 0.90 and 0.92) and the adductor muscle weight (AW) (R2 = 0.78 and 0.80). The strong functional relationship was also observed between TW and AW (R2 = 0.80 and 0.81). The relative condition factors (Kn) were high in both seasons. High meat yields were also observed in May (12.77 %) and September (14.26 %). The significant difference in meat yields (P < 0.05) can be a result of the seasonal difference manifested by the dynamics of energy partitioning during gametogenesis and spawning. These biological metrics are vital inputs in analysing mariculture prospects for the resource and a contribution to the scarce information on the biology of the species.