Effect of surface area to weight ratio of egg masses on the hatchability of Boophilus microplus eggs.
OBJECTIVE
On global basis, ticks transmit a number of pathogens than any other arthropod vector, and are among the most important vectors of diseases affecting humans, livestock and companion animals. Control of the vector has been focused on integrated management involving strategic use of insecticides, use of vaccines, use of herbal acaricides and breed resistance. It has been established that tick vaccine is working on limiting the egg laying potentiality and subsequent hatchability of the ticks fed on immunized animals. To generate entomological data following immunization of animals against ticks an experiment was conducted to establish the role of water content in egg masses for successful hatching into larvae.


METHODS
Different size and shape of egg masses of Boophilus microplus, Izatnagar isolate were obtained by manipulating the egg laying process. The weight of the egg masses was measured, keeping their integrity and surface areas of respective egg masses were calculated with the aid of computer software. Larvae hatched from the respective egg masses were counted individually.


RESULTS
It is clear that, with an increase in the exposed surface area of the cylindrical egg mass per unit weight, there is a reduction in the number of larvae hatched out. Also, the spherical egg masses significantly (0.026 at 95% confidence level) yielded more larvae per unit weight in comparison to the cylindrical egg masses.


CONCLUSIONS
It has been established that the larval count yielded from an egg mass is more or less dependent on the surface area : weight ratio of the respective egg masses rather than on either the surface area alone or weight of the egg mass alone.
Kurup
S P
SP
Entomology Laboratory, Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, India.
Azhahianambi
P
P
Ghosh
S
S
D000818:Animals; D001830:Body Surface Area; D004531:Eggs / Q000032:analysis*; D005260:Female; D018884:Ixodes / Q000033:anatomy & histology / Q000502:physiology*; D007814:Larva / Q000033:anatomy & histology*; D010058:Oviposition / Q000502:physiology*