Substrate moisture,particle size and temperature preferences of trap‐building larvae of sympatric antlions and wormlions from the rainforest of Borneo

1. Larvae of antlions (Neuroptera: Myrmeleontidae) and wormlions (Diptera: Vermileonidae) display a convergently evolved sit‐and‐wait hunting strategy of building pitfall traps in sandy areas. This study investigated a sympatric population of antlions and wormlions in the lowland rainforest of Borneo for substrate moisture, particle size and temperature preferences. It was hypothesised that these animals would show different preferences regarding these microhabitat traits. 2. The results showed that antlions had a higher aversion to moisture compared with wormlions, but that wormlions had a higher preference for small‐particle sand. Furthermore, thermal preferences in antlions and wormlions were significantly different, with antlions choosing higher temperatures. 3. The detected differences between antlions and wormlions might contribute to their niche partitioning in the mixed Bornean population and thus facilitate coexistence of these animals. It is possible that the hotter and dryer microhabitat edges are preferred by antlions.     

A protocol for temporal calibration of general area cladograms

Aim To describe a protocol for incorporating a temporal dimension into historical biogeographical analysis, while maintaining the essential independence of all datasets, involving the generation of general area cladograms. Location Global. Methods General area cladograms (GACs) are a reconstruction of the evolutionary history of a set of areas and unrelated clades within those areas. Nodes on a GAC correspond to speciation events in a group of taxa; general nodes are those at which multiple unrelated clades speciate. We undertake temporal calibration of GACs using molecular clock estimates of splitting events between extant taxa as well as first appearance data from the fossil record. We present two examples based on re‐analysis of previously published data: first, a temporally calibrated GAC generated from secondary Brooks parsimony analysis (BPA) of six extant bird clades from the south‐west of North America using molecular clock estimates of divergence times; and second, an analysis of African Neogene mammals based on a phylogenetic analysis for comparing trees (PACT) analysis. Results A hypothetical example demonstrates how temporal calibration reveals potentially critical information about the timing of both unique and general events, while also illustrating instances of incongruence between dates generated from molecular clock estimates and fossils. For the African Neogene mammal dataset, our analysis reveals that most mammal clades underwent geodispersal associated with the Neogene climatic optimum (c. 16 Ma) and vicariant speciation in central Africa correlated with increased aridity and cooler temperatures around 2.5 Ma. Main conclusions Temporally calibrated GACs are valuable tools for assessing whether coordinated patterns of speciation are associated with large‐scale climatic or tectonic phenomena.     

A comparison of life history traits of sexual and asexual strains of the parasitoid wasp,Lysiphlebus fabarum (Braconidae: Aphidiinae)

1. This study examined biological characteristics of sexual and asexual strains of the parasitoid wasp, Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae). 2. Strains were reared in different instar hosts (the black bean aphid, Aphis fabae Scopoli) under identical environmental conditions (21 °C, 65–75% RH, and LD 16:8 h). 3. Results showed that the second instar of the aphid is the most suitable growth stage for both strains, as the wasps that emerged from the second instar hosts were larger, more fecund, and had larger egg size. Trade‐offs between the fitness components of the parasitoid were clearer when the parasitoids were reared in suboptimal instars. 4. According to the results, sexual females emerged around 1 day earlier and lived around 0.5 day less than asexual females. Also, sexual females emerged with a lower initial egg load, although these wasps tend to have larger eggs than asexual females. Asexual females may enjoy greater longevity and higher developmental plasticity which suggests a higher degree of synchronization with pest population dynamism. 5. The results suggest that sexual wasps, in contrast to asexual wasps, invest more in egg size than in egg load. This study suggests strain‐specific adaptations of L. fabarum to different instars of the black bean aphid by which the allocation of nutritional resources to various functions differs between strains. 6. Furthermore, differences in life history traits between strains can greatly influence the population dynamics of each strain, and hence their effectiveness in suppressing pest populations.     

Pollen–plant–climate relationships in sub-Saharan Africa

Aim  To demonstrate that incorporating the bioclimatic range of possible contributor plants leads to improved accuracy in interpreting the palaeoclimatic record of taxonomically complex pollen types.
Location  North Tropical Africa.
Methods  The geographical ranges of selected African plants were extracted from the literature and geo-referenced. These plant ranges were compared with the pollen percentages obtained from a network of surface sediments. Climate-response surfaces were graphed for each pollen taxon and each corresponding plant species.
Results  Several patterns can be identified, including taxa for which the pollen and plant distributions coincide, and others where the range limits diverge. Some pollen types display a reduced climate range compared with that of the corresponding plant species, due to low pollen production and/or dispersal. For other taxa, corresponding to high pollen producers such as pioneer taxa, pollen types display a larger climatic envelope than that of the corresponding plants. The number of species contained in a pollen taxon is an important factor, as the botanical species included in a taxon may have different geographical and climate distributions.
Main conclusions  The comparison between pollen and plant distributions is an essential step towards more precise vegetation and climate reconstructions in Africa, as it identifies taxa that have a high correspondence between pollen and plant distribution patterns. Our method is a useful tool to reassess biome reconstructions in Africa and to characterize accurately the vegetation and climate conditions at a regional scale, from pollen data.