Molecular markers in populations of the spiders Lepthyphantes tenuis and Enoplognatha ovata

Spiders (Arachnida: Araneae) are important polyphagous predators which limit invertebrate pests in arable crops. To utilise them fully as part of an IPM (integrated pest management) programme a greater understanding of basic population dynamics and ecology is required.Due to their mobility and size, directly studying the population interactions of many invertebrate species is often impracticable. To infer spider population structure indirectly, this study employed a number of DNA based techniques: RAPD (Random Amplified Polymorphic DNA) analysis; PCR-RFLP (Polymerase Chain Reaction- Restriction Fragment Length Polymorphism) analysis; and the analysis of sequence data. In addition to examining variation per se, the sequencing of rDNA (ribosomal DNA) ITS (internal transcribed spacer) fragments allowed the phenomenon of concerted evolution to be studied in spiders for the first time.Two species commonly found on UK arable land: Lepthyphantes tenuis (Blackwall) and Enoplognatha ovata (Clerck) were studied. These species exhibit different rates of dispersal; the former a highly dispersive ballooning spider, the latter a more sedentary species, permitting the effect of dispersal on patterns of genetic variation to be examined.RAPD data were generated via five decamer primers and used to determine levels of variation between and within populations at a local scale ( 83% and L.tenuis > 54%). However, despite this high level of similarity, PCO (Principle Co-Ordinate) analysis of the E.ovata similarity data generated a pattern which could be related to the geographical separation of the populations. A less obvious structure was detected by PCO analysis of the L.tenuis similarity data. Further statistical analysis revealed that Fst (population sub-division) estimates were higher, and heterozygosity (gene diversity) levels lower for the E.ovata populations than the L. tenuis populations, emphasising that dispersal and gene flow reduce population structure.Analysis of rDNA was carried out with populations across a wider geographic scale. As an initial screen of variability PCR-RFLP of a rDNA fragment was undertaken, with L. tenuis from England, Scotland and New Zealand, and E. ovata from Invergowrie, Edinburgh and Elgin. Near identical intra-specific patterns were found. To investigate variation further, multiple ITS1 clones from an individual from each site were sequenced in both species. A total sequence variation of 2.7% was recorded across 10 E. ovata clones and 1.5% across 10 L. tenuis clones. Sequence variation was not population specific, but consisted of unique mutational events. The low variability across geographically distant populations is indicative of concerted evolution homogenising the rDNA array

Non-invasive genotyping and spatial mark-recapture methods to estimate European pine marten density in forested landscapes

Accurate population density estimates are important for conservation but can be difficult to obtain where species are elusive or rare. Non-invasive genotyping from hair or faeces has provided a promising solution and allowed individual identification from genotypes to inform population assessment models. We use individual genotypes derived from hair samples and Spatially Explicit Capture Recapture (SECR) models to estimate the population density of European pine marten (Martes martes) in three Scottish forests, then examine the effects of forest fragmentation on population size. Relative trends in pine marten abundance can be observed via changes in the number of scats in an area through time, but the link between this measure and population density remains unclear. We provide the first calibration of scat counts to enable population density estimation without the need for genetic analysis. Population density estimates ranged from 0.07 km-2 (95% CI 0.03 – 0.16) to 0.38 km-2 (95% CI 0.11 – 1.07), which were mid to low compared to other estimates from the Scottish population. An unequal sex ratio was found in one of the three forests. We found support for the previous finding that pine marten density in Scotland increases with forest fragmentation up to a threshold level (20 – 35% forest cover), beyond which it decreases. Our calibration suggests a non-linear relationship between scat counts and population density, although relatively small changes in population density result in marked changes in scat number. Following the recent re-introduction of pine martens to Wales, non-invasive genetic sampling for population estimation may provide an effective way of monitoring their progress

Root ectomycorrhizal status of oak trees symptomatic and asymptomatic for Acute Oak Decline in southern Britain

Acute Oak Decline (AOD) is a decline-disease that has distinctive symptoms and poses a serious threat to oak. Our understanding of the causal factors of AOD remains poor but it is likely that multiple biotic and abiotic factors contribute to a deterioration in oak condition. There is evidence that indications of above-ground tree health status are frequently reflected below-ground in roots and associated ectomycorrhizal (ECM) fungal communities. However, no study has yet explored these potential relationships specifically in AOD affected trees. In this study, we compare the composition and range of functional exploration types of ECM communities associated with AOD symptomatic oak trees and with AOD asymptomatic trees in three oak-dominated woodlands in southern England. We additionally assess the abundance of fine roots tips in surface soils beneath AOD symptomatic and asymptomatic trees and consider soil physico-chemical effects on ECM communities. The frequency of fine root tips was found to be significantly higher on asymptomatic compared with symptomatic trees in two of the three woodlands studied and long-distance ECM exploration types had a weak positive association with AOD asymptomatic trees. ECM diversity and composition were, however, unaffected by tree symptom status and were not related to the frequency of fine root tips. ECM diversity and compositional (but not exploration type) differences were evident only between the different woodlands and this was related to a small number of soil chemistry variables. This study revealed a relationship between the above-ground symptoms of AOD (i.e. stem lesions and Agrilus biguttatus exit holes) and the frequency of live root tips, providing a potential additional diagnostic tool of trees in decline and highlighting the importance of considering belowground rhizosphere microbiome communities

Testing the relative sensitivity of 102 ecological variables as indicators of woodland condition in the New Forest, UK.

Forests globally are facing an increasing number of threats from modified disturbance regimes, novel stressors and changing environmental conditions. This has ultimately resulted in declines in the ecological condition of many forest and woodland ecosystems, leading to widespread tree mortality and stand dieback. Effective indicators of overall woodland ecological condition are therefore needed for environmental monitoring and to support management responses. To test the effectiveness of different variables that could potentially be used as indicators of woodland condition, 102 variables that describe woodland structure, composition, functioning, edaphic conditions and disturbance regimes were assessed along 12 replicate gradients of beech stand dieback. Results indicated that 35 variables differed significantly between at least two stages of the dieback gradient, indicating their sensitivity to stand dieback. Seven of these indicators related to woodland species composition, two to functional processes, 20 to structural features, four to edaphic conditions, and two to disturbance regimes. These results demonstrate that effective indicators can potentially be identified for each of the ecological categories. Effective composition indicators included species richness of ectomycorrhizal fungi, ground flora and epiphytic lichens; functional indicators were soil respiration rate and net nitrification rate; edaphic conditions included soil Na:Ca ratio, exchangeable sodium, total carbon, Ca:Al ratio; structural indicators included canopy openness, litter cover, sward height, and volume of deadwood, and for disturbance the indicator was Equus dung density. Other measures, such as shrub cover and species richness of carabid beetles and spiders, were not found to vary significantly along the dieback gradients, and were therefore not identified as effective indicators. These results demonstrate the value of gradient analysis for evaluating indicators of woodland condition, but also highlight the need for multi-site studies to identify indicators with widescale applicability

Data from: Does cooperation mean kinship between spatially discrete ant nests?

Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation

Sample locations

Locations of nests used within this study along with triplet ID and their distance to forest cover historicall

Worker movement data

File containing ant worker movement data within sample triplets along with distance between nests and nest volumes. For full description of labelling see readm

Resource movement data

A four column file with data on the absorbance of individual ants following and ELISA assay. Arranges as follows: colony - the name of the tested triplet, n=10; nest - B, C or U for base, connected or unconnected (see paper Fig. 1 for details); sample - bl (blank, no ant), ctrl (control, known negative ant), 1-100 individual ants being tested for absorbance; absorb - absorbance valu

Microsatellite data

Data for microsatellite variation across 12 loci. Four columns preceeding mirosatellite data describing sampling (see readme), next 12 columns are variation across microsatellite dat