The Hertz Corporation

About: The Hertz Corporation is a based out in . It is known for research contribution in the topics: Population & Soil water. The organization has 9562 authors who have published 11044 publications receiving 447929 citations. The organization is also known as: Hertz Rental Car & Hertz Rent-a-Car.

The distribution of Endogone spores in some Australian and New Zealand soils, and in an experimental field soil at Rothamsted

Abstract: Some 250 Australian and New Zealand soil samples were examined. Endogone spores were usually more numerous and diverse in cultivated soils than under natural vegetation. It is suggested that the spores develop particularly under conditions of intermittent root growth. In a Rothamsted field soil that had received different manurial treatments (no manure, dung and mineral fertilizer) for over 100 years, spore populations differed greatly. The reliability of the sampling method is discussed.

The Role of the Queen in Preventing Oogenesis in Worker Honeybees

Abstract: SUMMARY1. Ovary development in worker honeybees is inhibited by 9-oxodecenoic acid or its vapour.2. A scent from the queen, in addition to her 9-oxodecenoic acid, also inhibits oogenesis in workers, but it is less effective than the acid. The scent and acid do not work together synergically.3. Neither 9-oxodecenoic acid nor queen scent, nor the two together, are as effective in inhibiting oogenesis in workers as access to a live queen. Older, mated queens are more effective than younger, virgin ones.4. Injection of 9-oxodecenoic acid partially inhibits ovary development in workers, but does not inhibit queen rearing by them.The mode of action of this acid is still uncertain.

Intra‐specific mechanisms in relation to the natural regulation of numbers of Aphis fabae Scop

Abstract: SUMMARY Parthenogenetic virginoparous apterae of Aphis fabae Scop. on field beans (Vicia faba) reproduced faster initially in populations of eight colonizing apterae than in those with 2–4 or 16–32 per plant. The aphids were at first mutually benefited but were quickly affected by competition as numbers rose above the critical density represented by about eight apterae and their first progeny. This is because the aphids remained densely aggregated and seemingly created a local shortage despite abundant food and space elsewhere on the plant. Such self-induced competition provides the basis for self-regulation of numbers of A. fabae in relation to (1) food and space provided by the growing plant and (2) mortality from natural enemies and from other causes including insecticides. As competition increased, the multiplication of A. fabae populations slowed, newly formed adult apterae emigrated and increasing numbers of alatae were formed. The mean weights of apterae decreased from about 1·8 mg. to 0·3 mg. and of alatae from 0·9 to 0·2 mg. Such decrease probably favours production of many adults that might otherwise fail to mature. Experiments in a glasshouse and in field cages indicated the success with which an A. fabae population adapts to and exploits a growing plant. Field bean plants sown in mid-March and infested as in the field produced an average of 15,000–17,000 A. fabae emigrants per plant of which 78–84% were adults (mostly alatae). This is equivalent to about 1600 million alate emigrants from 1 acre (0·4 hectare) of an infested field bean crop.