Desiccation plasticity in the embryonic life histories of non-annual rivulid species

Table 2 Period and desiccation effects on survival and development, by stage

Mortality rates - age-dependent baseline hazard
Stage	Period (Coef. (S.E.))	LTR	Desiccation treatment (Coef. (S.E.))	LTR
1		NS		NS
2		NS		NS
3		NS	2.79 (0.78)	Chisq = 13.25, df = 1, p = 0.0003
4	Interaction	Chisq =27.60, df = 3, P <0.0001	4.74 (1.16)	Chisq = 12.02, df = 1, p = 0.0005
5		NS		NS
Developmental rates - baseline hazard depends on time since entry in each stage
Stage	Period (Coef. (S.E.))	LRT	Desiccation treatment (Coef .(S.E.))	LRT
1		NS	-0.61 (0.14)	Chisq = 33.5, df = 4.83, p < 0.0001
2	When back in water - 1.61 (1.07)	Chisq =5.96, df = 1.68, P = 0.037	Interaction	Chisq = 21.73, df = 1.5, p < 0.0001
3	Interaction	Chisq = 24.79, df = 4, P <0.0001	-0.93 (0.25)	Chisq = 19.05 df = 1, p < 0.0001
4		NS	Interaction	Chisq = 14.72, df = 1, p = 0.0001
5		NS		NS
Hatching		NS		NS

A positive coefficient of an effect implies increased mortality or developmental rate, whereas negative coefficients indicate the opposite. The chi-square value (Chisq), degrees of freedom (df), and tail probabilities are given for each significant effect. Interactions of a treatment effect and pairs are indicated by ‘INTERACTION’ and these are further elaborated in Tables 3 and 4. For development in stage three, we also found an effect of the total number of days experienced in dry conditions. It reduces the development rate into stage four of embryos of pair one when returned to water by -13.157 (0.287) per day previously spent in dry conditions. The decrease in log-likelihood when this effect is added to the model is 13.77. NS indicates non-significant effects.

ISSN: 2041-9139