A new Indo-Australian genus of Braconinae (Insecta, Hymenoptera, Braconidae)

Bicarinibracon gen.n. (type species Atanyco1us tricolor . Szépligeti from Papua New Guinea and Irian Jaya). Bicarinibracon luteus gen. et. 3p.n. from India and Malaya and B. lepicius gen. et. sp.n. from Thailand and the Philippines are described and illustrated. A key to the specics of Bicarinibracon is provided and its systematic placement is discussed.     

Production of the chironomid Procladius bellus in an annual drawdown reservoir

SUMMARY. 1. In Laurel Creek Reservoir. Ontario, a small, eutrophic annual drawdown reservoir, some individuals of the chironomid Procladius bellus survive the winter drawdown.
2. With refilling of the reservoir in spring, colonization by P. bellus is continuous and there were three generations a year.
3. Production estimated by the size-frequency method was 117.12 kg (175 mg m⁻²) in 1980 and 70.14 kg (105 mg ^m-2) in 1981. Annual P:B was about 13 in both years.
4. Substantial slation-to-station variations in production occurred and overall production was lower than in shallow habitats.     

Determining uptake of 'non-labile' soil cadmium by Thlaspi caerulescens using isotopic dilution techniques

We assessed the ability of several populations of the metal-hyperaccumulator species, Thlaspi caerulescens , to mobilize non-labile cadmium in soils historically contaminated by Pb/Zn mine spoil or sewage sludge. Radio- labile Cd was determined chemically as an ' E -value', [Cd _E ], and biologically as an ' L -value', [Cd _L ]. For comparison, chloride-extractable Cd, [Cd_chlor], was also determined using 1 M CaCl₂ as a single-step soil extractant. Values of [Cd _L ] were measured for six populations of T. caerulescens that varied substantially in their ability to assimilate soil Cd, and a non-accumulator species with a similar growth habit, Lepidium heterophyllum . Seeds were sown in soil spiked with ¹⁰⁹Cd and grown for 9–12 wk in a controlled environment room. Values of [Cd _L ] were determined from the specific activity of ¹⁰⁹Cd and concentration of Cd in the plant leaves. For the six soils studied, [Cd _E ] ranged from 4.9 to 49% of total soil Cd [Cd_T]. Values of [Cd _L ] were, in general, in close agreement with both [Cd _E ] and [Cd_chlor] and substantially less than [Cd_T]. However, [Cd _L ] showed no correlation with the concentration of Cd in plant tissue, [Cd_shoot]. This suggests that, in the soils studied, T. caerulescens did not mobilize non-labile soil Cd by producing root exudates or altering rhizosphere pH. The results imply that there may be significant restrictions to metal bioavailability, even to hyperaccumulator species, in heavily contaminated soils in which a large proportion of the metal may be present in 'non-labile' forms.