Integrating Chemical Ecology with Behavioural Bioassays to Understand Host Preferences in Egg Parasitoids

Thomas E. Saunders*, Lee-Anne Manning, Kye Chung Park, Gregory I. Holwell, Gonzalo A. Avila

*https://orcid.org/0000-0003-1780-0314 | tom.saunders@auckland.ac.nz

This archive contains the raw data from a series of experiments with Trissolcus basalis and Trissolcus oenone to better understand the chemical basis mediating differences in host-specificity between these parasitoids. First, we compared the searching behaviour of T. basalis and T. oenone in open arena arrestment bioassays contaminated with footprint compounds from Nezara viridula and Cuspicona simplex. Trissolcus basalis spent four times longer searching for N. viridula than C. simplex, while T. oenone spent four times longer searching for C. simplex than N. viridula. We then conducted competition experiments to assess factors important to determining the outcomes of extrinsic and intrinsic contests between these parasitoids when they are simultaneously exposed to C. simplex egg masses. Trissolcus oenone, was the superior competitor in extrinsic and intrinsic contests. Finally, we recorded the antennal responses of T. basalis to egg extracts of N. viridula to tentatively identify potential contact kairomones used by this parasitoid to recognise and accept hosts. 

Description of directories, files, and variables:

/data 						Contains main data files.

arrestment.csv		Contains results from arrestment experiments between the 2 parastioids with contaminated arenas.

	date				Format day/month/year.	
	rep					An ID code for each replicate.
	wasp				Parasitoid species (tbas = T. basalis, toen = T. oenone).
	age					Age of wasp in days.
	pent				Pentatomid species (nvir = N. viridula, csim = C. simplex, ctrl = Control).
	sex					Sex of pentatomid.
	num					Number of pentatmoid females left in arena to contaminate it.
	arrest				Whether or not parasitoid displayed typical arrestment response.
	inner				Time (in seconds) parasitoid remained on paper within inner zone.
	total				Time (in seconds) parasitoid remained on paper.
	arena				An ID code for each arena.
	poo					Whether or not there were pentatomid feces visible on the arena.
	exit				The way the parasitoid left the arena (walk to edge or fly off the paper).	

competition.csv		Contains results of competition experiments between the 2 parasitoids on C. simplex egg masses.

	rep					An ID code for each replicate.
	treatment			Treatment, type of eggs (ctrl = Control, nvir = N. viridula, csim = C. simplex).
	pent				Species of pentatomid.
	eggs				Number of eggs in mass (excluding empty eggs).
	paper				Whether or not there was wax paper attached to the egg mass.
	date				Format day/month/year.
	focal				Focal parasitoid species to take behavioural observations from.
	t_contact			Time (in h:m:s) from focal parasitoid entry until first contact with an egg.
	first5_n			Number of eggs probed by focal parasitised before successfully parasitising 5 eggs. 
	first5_time			Time taken (in h:m:s) to successfully parasitise 5 eggs.
	total_time			Total time (in h:m:s) for competition treatment (up to 1 hour max).
	complete			Parasitoid species successfully ovipositing in all available eggs (tbas, toen, or both).
	eggs_tbas			Number of eggs successfully oviposited in by T. basalis.
	eggs_toen			Number of eggs successfully oviposited in by T. oenone.
	eggs_both			Number of eggs successfully oviposited in by both parasitoids.
	toen_won			For eggs oviposited in by both parasitoids, the number where T. oenone developed ('won' the contest).
	eggs_before_ag		Number of eggs focal parasitoid oviposited in before displaying aggression.
	tbas_em				Controls: Number of T. basalis emergence.
	toen_em				Controls: Number of T. oenone emergence.
	tbas_dev			Number of T. basalis developed (but not emerged).
	toen_dev			Number of T. oenone developed (but not emerged).
	pents				Number of pentatomids emerging.
	dev_pents			Number of pentatomids developed (but not emerged).
	undev				Number of eggs containing undifferentiated tissues.
	empty				Number of empty eggs in the mass.
	walk_ant			Behaviour: Walk-antennate host.
	turn				Behaviour: Turn.
	probe				Behaviour: Probe egg.
	pump				Behaviour: Pump ovipositor.
	mark				Behaviour: Mark egg.
	patrol				Behaviour: Patrol.
	non_ag				Behaviour: Non-aggressive interaction between parasitoids.
	back_agg			Behaviour: Backdown giver.
	back_rec			Behaviour: Backdown receiver.
	esc_agg				Behaviour: Escalate aggression.
	esc_rec				Behaviour: Receive escalated aggression.

eag-eag-norm.csv	Contains contains normalised EAG responses of T. basalis to control and solvent N. viridula egg rinses.

	file				Filename of autospike file.
	order				Order in which nvirxx_x responses were collected.
	wasp				T. basalis.
	figure				Figure letter.
	wasp_age			Age of parasitoid (in days).
	air					Response to puff of air (air control).
	hexane_1			Response to puff of hexane (hexane control) replicate 1.
	hexane_2			Response to puff of hexane (hexane control) replicate 2.
	hexane_3			Response to puff of hexane (hexane control) replicate 3.
	acetone_1			Response to puff of acetone (acetone control) replicate 1.
	acetone_2			Response to puff of acetone (acetone control) replicate 2.
	acetone_3			Response to puff of acetone (acetone control) replicate 3.
	e2d-std_1			Response to puff of E-2-decenal (E-2-decenal control) replicate 1.
	e2d-std_2			Response to puff of E-2-decenal (E-2-decenal control) replicate 2.
	e2d-std_3			Response to puff of E-2-decenal (E-2-decenal control) replicate 3.
	nvir96_1			Response to puff of 96hour immersion N. viridula eggs (96 hour treatment) replicate 1.
	nvir96_2			Response to puff of 96hour immersion N. viridula eggs (96 hour treatment) replicate 2.
	nvir96_3			Response to puff of 96hour immersion N. viridula eggs (96 hour treatment) replicate 3.
	nvir24_1			Response to puff of 24hour immersion N. viridula eggs (24 hour treatment) replicate 1.
	nvir24_2			Response to puff of 24hour immersion N. viridula eggs (24 hour treatment) replicate 2.
	nvir24_3			Response to puff of 24hour immersion N. viridula eggs (24 hour treatment) replicate 3.

	
ead-eag-raw.csv		Contains raw responses of T. basalis to control and solvent N. viridula egg rinses.

	file				Filename of autospike file.
	order				Order in which nvirxx_x responses were collected.
	wasp				T. basalis.
	figure				Figure letter.
	wasp_age			Age of parasitoid (in days).
	air					Response to puff of air (air control).
	hexane_1			Response to puff of hexane (hexane control) replicate 1.
	hexane_2			Response to puff of hexane (hexane control) replicate 2.
	hexane_3			Response to puff of hexane (hexane control) replicate 3.
	acetone_1			Response to puff of acetone (acetone control) replicate 1.
	acetone_2			Response to puff of acetone (acetone control) replicate 2.
	acetone_3			Response to puff of acetone (acetone control) replicate 3.
	e2d-std_1			Response to puff of E-2-decenal (E-2-decenal control) replicate 1.
	e2d-std_2			Response to puff of E-2-decenal (E-2-decenal control) replicate 2.
	e2d-std_3			Response to puff of E-2-decenal (E-2-decenal control) replicate 3.
	nvir96_1			Response to puff of 96hour immersion N. viridula eggs (96 hour treatment) replicate 1.
	nvir96_2			Response to puff of 96hour immersion N. viridula eggs (96 hour treatment) replicate 2.
	nvir96_3			Response to puff of 96hour immersion N. viridula eggs (96 hour treatment) replicate 3.
	nvir24_1			Response to puff of 24hour immersion N. viridula eggs (24 hour treatment) replicate 1.
	nvir24_2			Response to puff of 24hour immersion N. viridula eggs (24 hour treatment) replicate 2.
	nvir24_3			Response to puff of 24hour immersion N. viridula eggs (24 hour treatment) replicate 3.

gcms-cleaned.csv	Contains results of GCMS analysis of solvent egg extracts.

	sample_name			Name of sample analysed.
	rt					Retention time of compound.
	nist				NIST identification.	
	area				Compound area.
	kovats				Compound Kovats Index.
	Comments			Comments.

/data/autospike		Contains Autospike 3.9 files.

/data/images		Contains images of egg masses used in competition experiments.		
	
/figs				Contains figures generated by R code.

/src				Contains R code used for analyses.

arrestment.rmd		R markdown file with code for analyses.