Island bat diets: does it matter more who you are or where you live?

Differences in body size, echolocation call frequency and location may result in diet partitioning among bat species. Comparisons between island populations are one way to evaluate these competing hypotheses. We conducted a species-level diet analysis of three Rhinolophus and one Hipposideros species on the Philippine islands of Cebu, Bohol and Siquijor. We identified 655 prey (MOTUs) in the guano from 77 individual bats. There was a high degree of overlap among species' diets despite differences in body size and call frequency. For example, the diet of the 3 g-Hipposideros pygmaeus (mean CF = 102 kHz) exhibited a diet overlap higher than expected by chance with all three Rhinolophus species, even the 13 g-Rhinolophus inops (mean CF = 54 kHz). We observed more convergence in diet between Rhinolophus species and H. pygmaeus than between Rhinolophus species themselves, which may be explained by the broad diet of H. pygmaeus. There was less dietary overlap between Rhinolophus virgo from two islands than between R. virgo and congeners from Cebu. These data suggest that location causes convergence in diet, but specific species characteristics may drive niche specialization. The complex interplay between location and the perceptual ability of each species leads to a situation where simple explanations, for example body size, do not translate into predictable prey partitioning. In particular, our observations raise interesting questions about the foraging strategy and adaptability of the tiny H. pygmaeus.

Diet of the insectivorous bat Pipistrellus nathusii during autumn migration and summer residence.

Migration is widespread among vertebrates, yet bat migration has received little attention and only in the recent decades has a better understanding of it been gained. Migration can cause significant changes in behaviour and physiology, due to increasing energy demands and aerodynamic constraints. Dietary shifts, for example, have been shown to occur in birds before onset of migration. For bats, it is not known if a change in diet occurs during migration, although breeding season-related dietary preference has been documented. It is known that a diet rich in fats and the accumulation of fat deposits do increase the flight range of migratory bats. Some bat species can be regarded as long-distance migrants, covering up to 2000 km between summer and winter roosting areas. Pipistrellus nathusii (Vespertilionidae), a European long-distant migrant, travels each year along the Baltic Sea from north-eastern Europe to hibernate in central and southern Europe. This study presents data on the dietary habits of migrating Pipistrellus nathusii compared with those during the breeding season. We analysed faecal samples from bats on fall migration caught at the Ornithological Field Station in Pape, Latvia and from samples collected in North-Latvian summer roosts. We applied both morphological identification and molecular methods, as morphological methods also recognize life stages of prey and can contribute frequency data. The diets of bats on migration and breeding bats were similar, with Diptera and Lepidoptera comprising the major prey categories. However, certain prey groups could be explained by the different hunting habitats exploited during migration vs. summer residence.

Conservation genetics of the pond bat (Myotis dasycneme) with special focus on the populations in northwestern Germany and in Jutland, Denmark.

Conservation genetics is important in the management of endangered species, helping to understand their connectivity and long-term viability, thus identifying populations of importance for conservation. The pond bat (Myotis dasycneme) is a rare species classified as "Near Threatened" with a wide but patchy Palearctic distribution. A total of 277 samples representing populations in Denmark, Germany, Latvia, Hungary, and Russia were used in the genetic analyses; 224 samples representing Denmark, Germany, and Russia were analyzed at 10 microsatellite loci; 241 samples representing all areas were analyzed using mitochondrial D-loop and cytochrome B sequences. A Bayesian clustering approach revealed two poorly resolved clusters, one representing the Danish and German groups and the other the Russian group. However, significantly different pairwise F ST and D EST estimates were observed between the Danish and German groups and between the Danish and Russian groups suggesting a recent population structure. These conflicting results might be attributed to the effect of migration or low resolution due to the number of microsatellite markers used. After concatenating the two mitochondrial sequences, analysis detected significant genetic differentiation between all populations, probably due to genetic drift combined with a founder event. The phylogenetic tree suggested a closer relationship between the Russian and Northern European populations compared to the Hungarian population, implying that the latter belongs to an older ancestral population. This was supported by the observed haplotype network and higher nucleotide diversity in this population. The genetic structuring observed in the Danish/German pond bat stresses the need for a cross-border management between the two countries. Further, the pronounced mtDNA structuring, together with the indicated migration between nearby populations suggest philopatric female behavior but male migration, emphasizes the importance of protecting suitable habitat mosaics to maintain a continuum of patches with dense pond bat populations across the species' distribution range.

Molecular characterization of idiA and adjacent genes in the cyanobacteria Synechococcus sp. strains PCC 6301 and PCC 7942.

IdiA (iron-deficiency-induced protein A) is a protein expressed at highly elevated levels in Synechococcus sp. strains PCC 6301 and PCC 7942 under Fe- or Mn-limiting growth conditions. Besides being similar to two bacterial Fe-binding proteins, SfuA and FbpA, IdiA shows similarity to two ORFs (slr0513 and sir1295) of Synechocystis sp. PCC 6803. Northern blot analysis detected one transcript of about 1300 nt in RNA extracted from Synechococcus sp. PCC 6301 and PCC 7942 grown under Fe deficiency. The intensity of this transcript was considerably reduced in Fe-sufficient culture. It could be further shown that the regulation of IdiA expression is at the transcriptional level and that transcription and translation of IdiA are closely linked. Primer extension analysis indicated a single transcriptional start site 193 nt upstream of the first presumed translational start codon. Moreover, molecular characterization of the entire 5.8 kb chromosomal HindIII DNA fragment carrying the idiA gene from Synechococcus sp. PCC 6301 led to the identification of six long ORFs in addition to idiA. The two genes adjacent to idiA, and dpsA located 2018 nt downstream of idiA, were insertionally inactivated in Synechococcus sp. PCC 7942 and the corresponding mutants were partially characterized. These experiments provide evidence that the gene products of idiB, located immediately downstream of idiA, and of dpsA are involved in the activation of IdiA expression, since the absence of each of these two gene products prevents the greatly elevated expression of IdiA under nutrient deficiency.