The effect of temperature on times to hatching of eggs of the nematode Ostertagia circumcincta

A delayed gamma distribution satisfactorily described the distribution of times to hatching of Ostertagia circumcincta eggs incubated in 0.1% saline at temperatures between 6 and 20 degrees C. Below 6 degree C hatching of eggs was extremely variable. The relationship between rates of development and temperature within the range 10 to 20 degrees C was more closely described by a non-linear function than a linear one. The non-linear function was incorporated into a temperature summation equation which satisfactorily predicted the hatching of eggs incubated under conditions of alternating temperatures.