Applied Anthropology: Domains of Application

Applied Anthropology: Domains of Application . Satish Kediaand John van Willigen. Westport, CT: Greenwood Press, 2005. 376 pp.     

Induced carbon reallocation and compensatory growth as root herbivore tolerance mechanisms

Upon attack by leaf herbivores, many plants reallocate photoassimilates below ground. However, little is known about how plants respond when the roots themselves come under attack. We investigated induced resource allocation in maize plants that are infested by the larvae Western corn rootworm Diabrotica virgifera virgifera. Using radioactive ¹¹CO₂, we demonstrate that root‐attacked maize plants allocate more new ¹¹C carbon from source leaves to stems, but not to roots. Reduced meristematic activity and reduced invertase activity in attacked maize root systems are identified as possible drivers of this shoot reallocation response. The increased allocation of photoassimilates to stems is shown to be associated with a marked thickening of these tissues and increased growth of stem‐borne crown roots. A strong quantitative correlation between stem thickness and root regrowth across different watering levels suggests that retaining photoassimilates in the shoots may help root‐attacked plants to compensate for the loss of belowground tissues. Taken together, our results indicate that induced tolerance may be an important strategy of plants to withstand belowground attack. Furthermore, root herbivore‐induced carbon reallocation needs to be taken into account when studying plant‐mediated interactions between herbivores.     

Scale‐dependent longitudinal patterns in mussel communities

1. Species richness and assemblage patterns of organisms are dictated by numerous factors, probably operating at multiple scales. Freshwater mussels (Unionidae) are an endangered, speciose faunal group, making them an interesting model system to study the influence of landscape features on organisms. In addition, landscape features that influence species distributions and the scale at which the factors have the greatest impact are important issues that need to be answered to conserve freshwater mussels. 2. In this study, we quantified freshwater mussel communities at 16 sites along three mid‐sized rivers in the south‐central United States. We addressed the following questions: (i) Are there predictable longitudinal changes in mussel community composition? (ii) What landscape variables best explain shifts in community composition? and (iii) At what scale do landscape variables best predict mussel community composition? 3. After controlling for the influence of longitudinal position along the stream, we compared mussel distributions to a suite of hypothesised explanatory landscape variables across multiple scales – catchment scale (entire drainage area), buffer scale (100‐m riparian buffer of the entire catchment) and reach scale (100‐m riparian buffer extending 1 km upstream from the sampling site). 4. We found a significant and consistent longitudinal shift in dominant mussel species across all three rivers, with community composition strongly related to distance from the headwaters, which is highly correlated with stream size. After accounting for stream size, variables at the buffer scale were the best predictors of mussel community composition. After accounting for catchment position, mean channel slope was the best explanatory variable of community composition and appeared in all top candidate models at the catchment and buffer scales. Coverage of wetland and urban area were also correlated with community composition at the catchment and buffer scales. 5. Our results suggest that landscape‐scale habitat factors influence mussel community composition. Landscape features at the buffer scale performed best at determining community composition after accounting for position in the catchment; thus, further protection of riparian buffers will help to conserve mussel communities.     

Detecting the effects of environmental change above the species level with beetles in a fragmented tropical rainforest landscape

Abstract.  1. Invertebrate data identified to coarse groupings according to taxonomy or ecology are easier to obtain than species-level data. However, it is unclear if such data are suitable for detecting environmental change.
2. We compared the performance of four types of data (species, family, trophic group, and body size) to quantify the responses of beetle assemblages with three types of environmental change on the Atherton Tableland in north-eastern Queensland, Australia. Clearing of rainforest creates two levels of environmental change: first the extreme, forest loss, and second, the more subtle change associated with forest fragmentation. A strong rainfall gradient across the study landscape also influences the biota, imposing a third type of environmental change, independent of rainforest modification.
3. Almost 20 000 beetles were sampled from six replicate sites in each of pasture, small rainforest remnants, and both the edges and interiors of large rainforest remnants.
4. All four types of data showed significant multivariate differences in assemblage composition between pasture and rainforest sites. Species-level data in multivariate analyses showed an effect of fragmentation on small remnants and also showed variation which corresponded with the spatial aridity gradient across sites. Both of these patterns were only weakly evident or were non-existent at the level of family, trophic group, or body size class. No level of taxonomic resolution gave consistently stronger results when univariate tests were applied to individual component taxa.
5. We conclude that data above the species level may not have the sensitivity required to detect more subtle forms of environmental change.     

Impacts of Cyclone Larry on arboreal folivorous marsupials endemic to upland rainforests of the Atherton Tableland,Australia

Abstract Intense cyclones might be expected to adversely affect populations of arboreal mammals, either directly or as a consequence of the destruction of food resources and other key habitat elements. However, such impacts have rarely been quantified. The present study examined the response of five species of arboreal folivorous marsupials to Severe Cyclone Larry at nine sites in upland rainforests of the Atherton Tableland, north‐east Australia. Sites were originally surveyed for folivores in 1995–1997, and then resurveyed in 2006, 6–8 months after Cyclone Larry had traversed the region. All sites showed evidence of structural damage to vegetation, but overall damage levels (assessed in terms of canopy cover, damage to trees, basal area of dead trees and volume of woody debris) decreased from east to west across the study region. The detectability of rainforest possums increased after the cyclone. For the most commonly observed species, the proportion of individuals observed >5 m from survey transects was correlated with the amount of structural damage to vegetation. To avoid confounding changes in detectability with changes in abundance, only observations close (<5 m) to transects were used to estimate folivore abundance before and after the cyclone. On this basis, there were no significant differences between pre‐ and post‐cyclone abundance estimates for any folivore species. Further, changes in folivore abundance after the cyclone were not correlated with damage to vegetation across sites. Cyclone Larry does not appear to have caused a catastrophic loss of key habitat resources for marsupial folivores at the sites surveyed. The high degree of folivory practiced by marsupial folivores may help make them resilient to cyclone impacts. These conclusions are more robust for three commonly observed folivore species (Hemibelideus lemuroides, Pseudochirulus herbertensis and Trichosurus vulpecula johnstonii) than for two less frequently encountered species (Pseudochirops archeri and Dendrolagus lumholtzi).     

Characterization of SSRs from the American lobster,Homarus americanus

The American lobster (Homarus americanus), a commercially important benthic marine crustacean, is widely distributed along the continental shelf of the western North Atlantic. The population substructure of this species remains poorly understood despite its economic value. Informative markers are required to clarify relationships between local populations. To this end, we developed eight polymorphic short sequence repeats (SSR) for the American lobster, which were derived from expressed sequence tags. Additionally, we tested four SSRs previously identified for the Norway lobster (Nephrops norvegicus L.) for cross‐species utility; only one of these showed polymorphism.     

Adult and early‐stage characters of Brassolini contain conflicting phylogenetic signal (Lepidoptera,Nymphalidae)

This study examines the contribution of early‐stages and adult characters to the reconstruction of the phylogeny of Brassolini butterflies. Parsimony analyses used both equal weights and implied weights, and a series of analyses were performed. First, we analysed adult and early‐stages partitions independently and in combination for a subset of 27 species; in these cases the matrices were mostly complete. Whereas the adult partition alone produced a topology that was well resolved and congruent with previous studies, the early‐stages partition produced a poorly resolved tree under equal weights. Furthermore, implied weights produced a well‐resolved early‐stages topology that differed significantly from the adult topology. When both partitions were combined for 27 species, implied weights yielded a topology that resembled the adult tree except for the positions of Bia and Penetes, but statistical node support was generally lower. This suggests that stochastic noise increased when early‐stage characters were added to the adult partition, but the combined partitions topology was not statistically different from that based on adult characters alone. Second, given that preserved early stages are not as readily available as adults, we analysed a matrix including 45 species in which early‐stage data were missing for 18 species, and compared the topology to that produced by the adult partition alone. Results were similar to the analyses including fewer species; the combined partitions tree was similar to that from the adult partition except for the position of Bia and Penetes. We compare our findings to other genus‐level phylogenetic studies within Lepidoptera that have also used early‐stages and adult characters.     

FOOD RESOURCES, TERRITORY DENSITY AND REPRODUCTIVE SUCCESS OF AN ISLAND SILVEREYE POPULATION ZOSTEROPS LATERALIS

We examined the relationships between food resources, territory density and some breeding parameters (individual reproductive success and parental age) of a Capricorn Silvereye population during two years' detailed study on Heron Island, Great Barrier Reef. The territorial behaviour of the Silvereyes included dawn song. aggression and distinctive vocalizations. During both years, about 85% of pairs occupied territories although the population sizes differed. The dispersion pattern of territories was not regular and was correlated with the density of figs and human food scraps. Nestlings were fed more figs as they grew, and the parents foraged in fig trees outside their territories. However, only about 60%, of territorial pairs fledged young. Pairs which fledged most young were older, fed more insects to their nestlings, and nested in areas containing more fruiting fig trees per territory. We conclude that food resources were in short supply, and that access to fig trees provided breeding birds with a quick energy source while they searched for insect protein for the young. The data are consistent with the predictions of the ‘sufficient resource‘ hypothesis of the adaptive significance of territoriality but not with its assumption that the principal benefit is the food within the territory.     

Observation of some key stages of the embryonic development of Biomphalaria straminea (Dunker, 1848) (Molluska,Planorbidae)

Summary

Biomphalaria straminea is a freshwater snail and one of the intermediate hosts of the trematode parasite which causes schistosomiasis in Brazil. The main stages of embryonic development were analyzed with confocal laser scanning microscopy (CLSM), using the fluorescent probe DiOC and Nile Red as a vital stain in in vivo preparations. In fixed preparations nuclei were stained by the Feulgen reaction or the fluorescent DNA probe, Höechst 33342. Results obtained from the analysis of embryos at the stages of early cleavage, morula, blastula, gastrula, early trocophore and veliger showed that these stages are similar to those described for Biomphalaria glabrata and Biomphalaria tenagophila. CLSM optical sections of early trochophore showed important morphological structures such as the blastopore, stomodeum and shell gland; and in early veliger, internal organs such as the esophagus, stomach and male and female ducts were also clearly identified.