DOI: 10.5061/dryad.5t5m4
title: Data from: Evolution of behavioral and cellular defenses against parasitoid wasps in the Drosophila melanogaster subgroup

description: It may be intuitive to predict that host immune systems will evolve to
 counter a broad range of potential challenges through simultaneous
 investment in multiple defenses. However, this would require diversion of
 resources from other traits, such as growth, survival, and fecundity.
 Therefore, ecological immunology theory predicts that hosts will
 specialize in only a subset of possible defenses. We tested this
 hypothesis through a comparative study of a cellular immune response and a
 putative behavioral defense used by eight fruit fly species against two
 parasitoid wasp species (one generalist and one specialist). Fly larvae
 can survive infection by melanotically encapsulating wasp eggs and female
 flies can potentially reduce infection rates in their offspring by laying
 fewer eggs when wasps are present. The strengths of both defenses varied
 significantly but were not negatively correlated across our chosen host
 species; thus, we found no evidence for a trade-off between behavioral and
 cellular immunity. Instead, cellular defenses were significantly weaker
 against the generalist wasp, whereas behavioral defenses were similar in
 strength against both wasps and positively correlated between wasps. We
 investigated the adaptive significance of wasp-induced oviposition
 reduction behavior by testing whether wasp-exposed parents produce
 offspring with stronger cellular defenses, but we found no support for
 this hypothesis. We further investigated the sensory basis of this
 behavior by testing mutants deficient in either vision or olfaction, both
 of which failed to reduce their oviposition rates in the presence of
 wasps, suggesting that both senses are necessary for detecting and
 responding to wasps.
description: Figure 1, phylogenetic
 treeNexus file executable in
 MrBayes that was used to generate the tree from aligned and trimmed Amyrel
 sequences (GenBank accession numbers in the Supporting Information). Tree
 file created in FigTree from the resulting 50% majority rule consensus
 phylogeny.Fig1.zipFigure 2, cellular immunityFor all replicates of every fly-wasp species combination, number of dissected larvae that were attacked (contained a parasitoid egg), unattacked, or multiply attacked (contained &gt;1 parasitoid egg). Number of surviving larvae that were moved to food vials to measure eclosion success (larvae_moved), which involved four possible outcomes: (i) fly emerges without a melanized capsule (unattacked_fly), (ii) fly emerges with a melanized capsule (fly_survived), (iii) wasp emerges (wasp_survived), or (iv) both insects die (death). Proportional eclosion outcomes (ii)-(iv) (fly_success, wasp_success, and death_rate) were calculated after subtracting unattacked_fly from larvae_moved, such that unattacked fly larvae were ignored in the analyses.Fig2.csvFigure 3, oviposition maintenanceNumber of eggs laid over 5-day forced co-habitation assays by flies in vials without wasps (ctrl), with L. boulardi (Lb17), and with L. heterotoma (Lh14), where each row represents a vial. For each day (#1-5), f# is the number of female flies alive at the beginning of the day, e# is the number of eggs laid by the end of the day, and c# is the cumulative number of eggs laid per female, i.e. c1 = e1/f1, c2 = c1 + e2/f2, c3 = c2 + e3/f3, etc. Sets of replicates for each fly species are arranged by date; control and wasp vials were run simultaneously in approximately equal numbers and multiple groups were run if &lt;5 vials per treatment. day5_dOR = (c5 for each Lb17 or Lh14 replicate) / (mean c5 across control vials run for the same fly species at the same time). Oviposition maintenance indices in Fig. 3 are mean day5_dOR across all Lb17 or Lh14 replicates for each fly species.Fig3.csvFigure 4, trade-offsNewick tree file (same as Fig. 1) and "infiles" for Lb17 and Lh14, with mean cellular immunity index in column 1 and mean oviposition maintenance index in column 2 for each fly species, used as inputs for the Contrast program in PHYLIP v. 3.69. Phylogenetically independent contrasts from the resulting "outfiles" are compiled into Fig4.csv: cellular immunity index contrasts (CI_Lb17 and CI_Lh14) and oviposition maintenance index contrasts (OMI_Lb17 and OMI_Lh14).Fig4.zipFigure 5a, D. yakuba ovipositionNumber of eggs laid over a 6-day forced co-habitation assay by D. yakuba in vials without wasps (control), with L. boulardi (exp_Lb17), and with L. heterotoma (exp_Lh14). Number of females in each vial at the start of the experiment (none of them died during the experiment), eggs# = eggs laid on days #1-6, total_eggs = sum from eggs1:eggs6, eggs_per_female = total_eggs / females.Fig5a.csvFigure 5b, D. yakuba offspring survivalEggs laid by D. yakuba in the three parental treatments (control, exp_Lb17, and exp_Lh14) were transferred to Petri dishes, grown to second instar, then exposed to female L. boulardi. The larvae were moved to food vials to eclose and egg-to-adult survival was measured. capsule = adult flies that had melanized capsules and thus survived parasitism; no_capsule = adult flies that did not have capsules and thus were not attacked as larvae; total = capsule + no_capsule.Fig5b.csvFigure 6, sight and smell mutantsNumber of eggs laid over 5-day forced co-habitation assays by flies in vials without wasps (ctrl), with L. boulardi (LB17), and with L. heterotoma (LH14), where each row represents a vial. Four D. melanogaster strains are represented: Orco2 = smell-deficient mutant, GMRhidII = sight-deficient mutant, w1118 = white-eyed mutant, OregonR = wild-type. For each day (#1-5), e# is the number of eggs laid by the end of the day, f# is the number of female flies alive at the beginning of the day, and cu# is the cumulative number of eggs laid per female, i.e. cu1 = e1/f1, cu2 = cu1 + e2/f2, cu3 = cu2 + e3/f3, etc.Fig6.csvFigure S1, melanogaster / simulans adaptive significanceD. melanogaster and D. simulans offspring produced in embryo collection chambers without wasps (control) and with Lb17 or Lh14 (wasp) were grown to second instar, then exposed to wasps. fly_win = number of flies that survived with melanized capsules; wasp_win = number of wasps that survived; death = number of larvae that did not eclose.FigS1.csv