Plasticity in host utilization by two host-associated populations of Aphis gossypii Glover.

Biological and morphological plasticity in polyphagous insect herbivores allow them to exploit diverse host plant species. Geographical differences in resource availability can lead to preferential host exploitation and result in inconsistent host specialization. Biological and molecular data provide insights into specialization and plasticity of such herbivore populations. In agricultural landscapes, Aphis gossypii encounters several crop and non-crop hosts, which exist in temporal and spatial proximity. We investigated the host-specialization of two A. gossypii host-associated populations (HAPs), which were field collected from cotton and squash (cotton-associated population and melon-associated population), and later maintained separately in the greenhouse. The two aphid populations were exposed to seven plant species (cotton, okra, watermelon, squash, cucumber, pigweed, and morning glory), and evaluated for their host utilization plasticity by estimating aphid's fitness parameters (nymphal period, adult period, fecundity, and intrinsic rate of increase). Four phenotypical characters (body length, head capsule width, hind tibia length and cornicle length) were also measured from the resulting 14 different HAP × host plant combinations. Phylogenetic analysis of mitochondrial COI sequences showed no genetic variation between the two HAPs. Fitness parameters indicated a significant variation between the two aphid populations, and the variation was influenced by host plants. The performance of melon-aphids was poor (up to 89% reduction in fecundity) on malvaceous hosts, cotton and okra. However, cotton-aphids performed better on cucurbitaceous hosts, squash and watermelon (up to 66% increased fecundity) compared with the natal host, cotton. Both HAPs were able to reproduce on two weed hosts. Cotton-aphids were smaller than melon-aphids irrespective of their host plants. Results from this study suggest that the two HAPs in the study area do not have strict host specialization; rather they exhibit plasticity in utilizing several hosts. In this scenario, it is unlikely that host-associated A. gossypii populations would evolve into host-specific biotypes.

Assessing Genetic Diversity in Four Stink Bug Species, Chinavia hilaris, Chlorochroa uhleri, Chlorochroa sayi, and Thyanta pallidovirens (Hemiptera: Pentatomidae), Using DNA Barcodes.

Stink bugs (Hemiptera: Pentatomidae) are an economically important group of insects that attack numerous crops in the central valley of California. Management of these pests using pheromones or biological control can be species specific, and proper identification of insect species is essential for effective management. The objective was to examine genetic variability in four species of stink bugs, which included Chinavia hilaris (Say) (= Acrosternum hilare) (Hemiptera: Pentatomidae) , Chlorochroa uhleri (Stål) (Hemiptera: Pentatomidae) , Chlorochroa sayi (Stål) (Hemiptera: Pentatomidae), and Thyanta pallidovirens (Stål) (Hemiptera: Pentatomidae) and to determine whether there may be cryptic species present. Stink bugs were collected in pistachios or on adjacent vegetation when abundant in the central valley of California. The mitochondrial DNA cytochrome oxidase I (COI) gene region (i.e., the barcode) was sequenced for each individual. Data were combined with available GenBank accessions for each species and used to construct a phylogenetic tree. Divergence between genera ranged from 11.2 to 15.7%, whereas divergence between the two Chlorochroa spp. was 4.6%. Genetic variation within Chinavia hilaris collections was up to 4.7%, which suggests the presence of a cryptic species. Genetic divergence was highest between individuals of Chinavia hilaris from the west coast and the east coast of the United States. In contrast, genetic variation within individuals of C. uhleri and Ch. sayi was less than 1%. Nine haplotypes were found for Chinavia hilaris, five for C. uhleri, three for Ch. sayi, and five for T. pallidovirens. The relevance of correct species identification and genetic diversity to stink bug management practices was discussed.

Acute kidney injury associated with ingestion of star fruit: Acute oxalate nephropathy.

Starfruit (Averrhoa carambola) and its juice are popular in the Indian subcontinent as an indigenous medicine. Oxalate concentration in this fruit and it's freshly prepared juice is very high. We present a report of patients presenting with acute kidney injury due to oxalate nephropathy admitted in a single center. All patients had history of ingesting star fruit. Patients became symptomatic after 10-12 h of eating and main symptoms were pain abdomen and decrease in urine output. Three patients needed hemodialysis. All improved with complete renal recovery. Taking star fruit in large amount on an empty stomach and in a dehydrated state is a risk factor for nephrotoxicity.

Transmission of Pantoea ananatis and P. agglomerans, causal agents of center rot of onion (Allium cepa), by onion thrips (Thrips tabaci) through feces.

Frankliniella fusca, the tobacco thrips, has been shown to acquire and transmit Pantoea ananatis, one of the causal agents of the center rot of onion. Although Thrips tabaci, the onion thrips, is a common pest of onions, its role as a vector of P. ananatis has been unknown. The bacterium, P. agglomerans, is also associated with the center rot of onion, but its transmission by thrips has not been previously investigated. In this study, we investigated the relationship of T. tabaci with P. ananatis and P. agglomerans. Surface-sterilized T. tabaci were provided with various acquisition access periods (AAP) on onion leaves inoculated with either P. ananatis or P. agglomerans. A positive exponential relationship was observed between thrips AAP duration and P. ananatis (R² = 0.967; P = 0.023) or P. agglomerans acquisition (R² = 0.958; P = 0.017). Transmission experiments conducted with T. tabaci adults indicated that 70% of the seedlings developed center rot symptoms 15 days after inoculation. Immunofluorescence microscopy with antibodies specific to P. ananatis revealed that the bacterium was localized only in the gut of T. tabaci adults. Mechanical inoculation of onion seedlings with fecal rinsates alone produced center rot but not with salivary secretions. Together these results suggested that T. tabaci could efficiently transmit P. ananatis and P. agglomerans.