Table 1.
Description of statistical models applied to analyse the influence of first and second blood meal type (P. chabaudi infected or uninfected) on the feeding behaviour and infection susceptibility of An. stephensi mosquitoes. In 'Group Analysed', details of the subset of mosquitoes included in a particular analysis are given, with 'first feed' indicating the type of blood meal they were first given (I – only mosquitoes first fed infected blood, I + U – mosquitoes whose first feed was infected or uninfected). In analyses of mosquitoes of whose first feed was infected (models 2,3,5–8), the 'oocyst present' column indicates whether all mosquitoes were included (-), or just those that developed oocysts (Y). The 'took a second feed' column indicates whether analysis was performed on all mosquitoes that had a first blood meal (-), or just those who took a first and second blood meal (Y). N gives the number of mosquitoes included in each analysis. 'Maximal Model' gives the complete set of factors in addition to wing size that were included as explanatory variables for each response variable, with terms in brackets indicating nested variables. Explanatory variables are: FEED1 – status of first blood meal (I or U), FEED2 – status of second blood meal (I or U), with MOUSE1 and MOUSE2 representing the particular mouse within each treatment group that mosquitoes fed on in the first and second feeding trial, respectively. The superscripta denotes variables that were fit as random effects, all others being treated as fixed effects.
| Parameter of Interest | Response Variable | Group Analyzed | N | Model No. | Maximal model (not listing wing size) | SAS subroutine | ||
| First feed | Oocysts present | Took a 2nd feed | ||||||
| Blood Feeding | Had a 2nd blood feed | I + U | - | - | 352 | 1 | F1 + F2(F1) + M1(F1) + M2(F2) | PC |
| I | - | - | 75 | 2 | Oocyst presence + F2 + M2(F2) | PG | ||
| I | Y | - | 45 | 3 | Oocyst number + F2 + M2(F2) | PG | ||
| Log (size of 2nd blood meal) | I+U | . | Y | 167 | 4 | F1+ F2(F1) + Ml(Fl)a + M2(F2)a | PM | |
| I | - | Y | 51 | 5 | Oocyst presence + F2 + Ml(F2)a + M2(F2)a | PM | ||
| I | Y | Y | 34 | 6 | Oocyst number + F2 + Ml(F2)a + M2(F2)a | PM | ||
| Infection Rate | Oocyst presence | I | - | Y | 54 | 7 | F2 + M1 | PG |
| Log(oocyst no.) | I | Y | Y | 34 | 8 | F2 + Ml a | PM | |