Additional notes on the life history of the Tagula Honeyeater Microptilotis vicina in Papua New Guinea

We revisited a location to study previously individually marked Tagula Honeyeaters Microptilotis vicina in 2019, 3 years after the original 2016 study on Junet Island, Louisiade Archipelago, Papua New Guinea. Re-encountered Tagula Honeyeaters indicated sedentary behaviour across years and an average annual adult survival rate of ≥0.75. We made the first observations of building and laying at two nests, and recorded nesting habits in the species. Tagula Honeyeaters showed the general trend in the honeyeater family of only the female building the nest and incubating. Nests were similar to those previously observed and to those of related species. Clutch-size in both nests was two and laying was on consecutive days. Eggs were white to off-white, with a ring of liver-brown spots and markings around the larger end. Incubation began on the day that the second egg was laid and lasted 14 days in both nests. Males visited the nest area only after the eggs hatched. At one nest, the nestling period was suspected to be 12 days. These limited observations of the only endemic island representative in Microptilotis indicate that, like plumage characters, breeding parameters remain similar within the genus.

EFFECTS OF CARBOSULFAN ON THE BIOLOGY OF BIRD CHERRY OAT APHID

Aphids are the most commonly occurring, destructive, sap sucking and serious threat to cereal crops especially wheat (Triticum aestivum). Bird Cherry Oat aphid Rhopalosiphum padi (L.), is one of the most important aphids on T. aestivum which is one of the most consumed food and a source of nutrition in Pakistan. It causes considerable yield loss in wheat. Carbosulfan, a carbamate, is of the most commonly used pesticide against R. padi. The effects of Carbosulfan on generations of R. padi were performed under standard lab conditions by exposing adult aphids to three different concentrations (1.4×10-7 ppm, 1.4×10-10 ppm, 1.4×10-13 ppm) of Carbosulfan (Advantage® EC). Based on the results, all three concentrations noticeably reduced the pre-adult survival rate. 1.4×10-13 significantly extended the development duration of 1st instar, 2nd instar and 3rd instar nymphs. 1.4×10-13 ppm also extended the total pre-adult period and female longevity of R. padi. The total longevity was increased by 1.4×10-10 ppm. However, the fecundity decreased the most at 1.4×10-10 ppm. While the TPRP and APRP increased the most at 1.4×10-13 ppm. In the life table parameters, both the intrinsic rate of increase (r) and the finite rate of increase (ƛ) decreased at 1.4×10-7 ppm and 1.4×10-10 ppm, as well as the net reproductive rate (R0) also decreased at 1.4×10-7 ppm and 1.4×10-10 ppm, while mean generation time (T) showed increase at 1.4×10-13 ppm. Thus, at the concentrations of Carbosulfan tested here, there were negative impacts on R. padi fitness and biology by decreased pre-adult survival rate, λ, r, and R0. The concentrations also slowed down the development of some stages and extended T. My results would be helpful in assessing the overall effects of Carbosulfan on R. padi and should be taken into consideration when use Carbosulfan as a seed dressing insecticide for management of R. padi in wheat crop.