Inhibiting aphid wing development: is immune challenge important?

Aphids show inhibition of wing development when parasitized by hymenopteran parasitoids, especially when parasitism takes place early in the host's development. The present study tests the hypothesis that the aphid itself redirects the resources needed for the development of wings to support the immune response, rather than the parasitoid directly promoting wing inhibition. When the aphid's immune system is challenged with bacterial antigens and a fungal pathogen, neither immune challenge alters wing development, indicating that perhaps there is no redirection by the aphid of resources required for wing development to cover possible costs of mounting an immune response.     

Improving biodiversity monitoring

Effective biodiversity monitoring is critical to evaluate, learn from, and ultimately improve conservation practice. Well conceived, designed and implemented monitoring of biodiversity should: (i) deliver information on trends in key aspects of biodiversity (e.g. population changes); (ii) provide early warning of problems that might otherwise be difficult or expensive to reverse; (iii) generate quantifiable evidence of conservation successes (e.g. species recovery following management) and conservation failures; (iv) highlight ways to make management more effective; and (v) provide information on return on conservation investment. The importance of effective biodiversity monitoring is widely recognized (e.g. Australian Biodiversity Strategy). Yet, while everyone thinks biodiversity monitoring is a good idea, this has not translated into a culture of sound biodiversity monitoring, or widespread use of monitoring data. We identify four barriers to more effective biodiversity monitoring in Australia. These are: (i) many conservation programmes have poorly articulated or vague objectives against which it is difficult to measure progress contributing to design and implementation problems; (ii) the case for long‐term and sustained biodiversity monitoring is often poorly developed and/or articulated; (iii) there is often a lack of appropriate institutional support, co‐ordination, and targeted funding for biodiversity monitoring; and (iv) there is often a lack of appropriate standards to guide monitoring activities and make data available from these programmes. To deal with these issues, we suggest that policy makers, resource managers and scientists better and more explicitly articulate the objectives of biodiversity monitoring and better demonstrate the case for greater investments in biodiversitymonitoring. There is an urgent need for improved institutional support for biodiversity monitoring in Australia, for improved monitoring standards, and for improved archiving of, and access to, monitoring data. We suggest that more strategic financial, institutional and intellectual investments in monitoring will lead to more efficient use of the resources available for biodiversity conservation and ultimately better conservation outcomes.     

Body condition, territory ownership and age-related reproductive performance in Spruce Grouse Dendragapus canadensis hens

Adult Spruce Grouse Dendragapus canadensis hens show better reproductive performance (i.e. larger clutch size, earlier clutch initiation, higher frequency of renesting) than year-lings. Body and breast muscle weights, condition indices and relative body composition were compared between adult and yearling birds from northeastern Ontario, Canada, to determine whether differences in endogenous reserves mobilized for egg production and (or) territory ownership could explain these differences in reproductive performance. Adults and yearlings showed similar declines in body-weight, breast muscle weight and condition indices from the pre-laying to the post-laying period, but no significant interage differences emerged at any stage of the breeding season. Changes in body composition, especially gut structure, were similar in all birds; this result is consistent with a dietary shift in both age classes from a fibrous winter diet to more succulent foods in spring. Non-territory-holding (replacement) yearlings also had similar body-weights and breast muscle weights and were in similar condition to territory holders (residents) in the pre-laying period. My findings do not support the hypothesis that differences in body condition and territory occupancy can account for differences in age-related reproductive performance in Spruce Grouse.     

Maintenance of genetic variation in plants and pathogens involves complex networks of gene-for-gene interactions

The RPP13 [recognition of Hyaloperonospora arabidopsidis (previously known as Peronospora parasitica )] resistance ( R ) gene in Arabidopsis thaliana exhibits the highest reported level of sequence diversity among known R genes. Consistent with a co-evolutionary model, the matching effector protein ATR13 ( A. thaliana -recognized) from H. arabidopsidis reveals extreme levels of allelic diversity. We isolated 23 new RPP13 sequences from a UK metapopulation, giving a total of 47 when combined with previous studies. We used these in functional studies of the A. thaliana accessions for their resistance response to 16 isolates of H. arabidopsidis . We characterized the molecular basis of recognition by the expression of the corresponding ATR13 genes from these 16 isolates in these host accessions. This allowed the determination of which alleles of RPP13 were responsible for pathogen recognition and whether recognition was dependent on the RPP13/ATR13 combination. Linking our functional studies with phylogenetic analysis, we determined that: (i) the recognition of ATR13 is mediated by alleles in just a single RPP13 clade; (ii) RPP13 alleles in other clades have evolved the ability to detect other pathogen ATR protein(s); and (iii) at least one gene, unlinked to RPP13 in A. thaliana, detects a different subgroup of ATR13 alleles.     

Melanoma,Growth Factors,and Cutaneous Paraneoplastic Syndromes

Paraneoplastic syndromes are systemic reactions in patients with cancers that are unrelated to tumor size or location. Cutaneous paraneoplastic syndromes include proliferative, metabolic, and inflammatory skin disorders. Both systemic and cutaneous paraneoplastic reactions may occur in patients with malignant melanoma. Cancers, including melanoma, may produce growth factors, which may be responsible for proliferative cutaneous paraneoplastic syndromes. A patient with malignant melanoma we previously reported, who had the sudden onset of acanthosis nigricans, skin tags (acrochordons), and seborrheic keratoses provides a model for proliferative cutaneous paraneoplastic syndromes. High levels of α-TGF were found in the patient's urine prior to melanoma removal. The increased level of α-TGF declined after the melanoma was removed, and a corresponding clinical improvement in his acanthosis nigricans, skin tags, and seborrheic keratoses occurred. In the skin lesions, EGF receptors were abnormally present throughout all epidermal layers prior to melanoma removal, and returned to their normal distribution in the basal layers after surgery. Ectopic growth factor production by malignant melanomas and other epithelial neoplasms may cause rare, but distinctive cutaneous paraneoplastic lesions. The model of melanoma, cutaneous paraneoplastic syndromes, and growth factors may provide understanding of both cutaneous lesions associated with neoplasia, and benign cutaneous lesions.     

The whole mitochondrial genome sequence of the zebra finch (Taeniopygia guttata)

Here we describe the complete nucleotide sequence of the mitochondrial genome (16 583/4 bp) of the zebra finch (Taeniopygia guttata). Primers were designed based on highly conserved regions of an alignment of three passerine complete mitochondrial DNA (mtDNA) sequences. A combination of overlapping long polymerase chain reaction (PCR) purification, followed by fully nested PCR and sequencing was used to determine the complete mtDNA genome. Six birds, from distinct maternal lineages of a pedigreed population were sequenced. Five novel haplotypes were identified. These sequences provide the first data for sequence variation across the whole mitochondrial genome of a passerine bird species.     

Density-Dependent Harvest Modeling for the Eastern Wild Turkey

Abstract Many current wild turkey (Meleagris gallopavo) harvest models assume density-independent population dynamics. We developed an alternative model incorporating both nonlinear density-dependence and stochastic density-independent effects on wild turkey populations. We examined model sensitivity to parameter changes in 5% increments and determined mean spring and fall harvests and their variability in the short term (3 yr) and long term (10 yr) from proportional harvesting under these conditions. In the long term, population growth rates were most sensitive to poult:female ratios and the form of density dependence. The nonlinear density-dependent effect produced a population that maximized yield at 40% carrying capacity. The model indicated that a spring or fall proportional harvest could be maximized for fall harvest rates between 0% and 13% of the population, assuming a 15% spring male harvest and 5% spring illegal female kill. Combined spring and fall harvests could be maximized at a 9% fall harvest, under the same assumptions. Variability in population growth and harvest rates increased uncertainty in spring and fall harvests and the probability of overharvesting annual yield, with growth rate variation having the strongest effect. Model simulations suggested fall harvest rates should be conservative (≤9%) for most management strategies.     

Perception of volatiles associated with sex and food by different adult forms of the black bean aphid, Aphis fabae

Abstract. Electroantennograms (EAGs) were recorded from adult male and asexual forms (winged and wingless virginoparae and gynoparae) of the black bean aphid, Aphis fabae , during stimulation with two sex pheromone components, (+)-(4a S ,7 S ,7a R )-nepetalactone and (-)-(1 R ,4a S ,7 S ,7a R )-nepetalactol, as well as six plant volatiles, i.e. ( E )-2-hexenal, ( E )-2-hexenol-1, ( Z )-3-hexenol-1, ( Z )-3-hexenyl acetate, hexanal and allyl isothiocyanate. The male antennae are 1000-10,000 times more sensitive to nepetalactol and nepetalactone than to the plant compound ( E )-2-hexenal. Besides this marked difference of EAG peak responses in males, the EAG rise and decay are slower for the sex pheromone components. Males are also much more sensitive to the sex pheromone components than asexual females. This high sensitivity correlates with a predominance of antennal secondary rhinaria, the major sites of pheromone perception in the male. However, it is the primary rhinaria on the antennae of the wingless asexual females that are responsible for pheromone perception. Male antennae are as responsive as the asexual female antennae to the plant volatiles. The specialization of the male for mate location is discussed.     

Odour‐mediated orientation behaviour of the lily beetle Lilioceris lilii

The lily beetle Lilioceris lilii (Scopoli) (Coleoptera: Chrysomelidae) feeds on Lilium, Fritillaria and Cardiocrinum plants and is a serious pest in gardens and amenity plantings in parts of Northern Europe and North America. In the present study, the odour‐mediated behaviour of L. lilii is investigated by behavioural bioassays using a linear‐track olfactometer. The behavioural responses of L. lilii to hosts and conspecifics are, at least in part, odour‐mediated and the responses differ with respect to the physiological (reproductive) state of the adult beetle (i.e. pre‐ or post‐diapause). Significantly more diapaused female L. lilii move into air streams containing the odour of intact host plants than into clean air, and move into air streams containing odour of host plants and beetles combined in preference to odour from manually‐damaged host plants. Diapaused females also move into air streams containing odours from intact plants over those from larval‐infested plants. Pre‐diapause males move into the air streams of intact plants rather than L. lilii‐infested plants. Pre‐diapause females show no significant response in any experiment. The data indicate that the odour‐mediated responses of L. lilii are consistent with those known for other chrysomelids that produce a male aggregation pheromone to which reproductive individuals of both sexes respond.