Petri dish effect of hyperparasitoids
Data files
Jan 16, 2025 version files 8.96 KB
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Exp_1.csv
1.23 KB
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Exp2_2.csv
909 B
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Exp2_3_and_2_4.csv
1.84 KB
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Exp2.1.csv
2.03 KB
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README.md
2.95 KB
Abstract
In nature, resources necessary for reproduction and survival are often spatially distributed or scarce. Parasitoid wasps are insects that develop as larvae in or on a single invertebrate resource (often another insect), while the adults are free living. Parasitoid larvae, exploit hosts for reproduction, while adults rely on carbohydrates, e.g. floral nectar, for maintenance. Finding these different resources may affect fitness related traits such as fecundity and survival. We compared reproduction and longevity in a hyperparasitoid wasp, Gelis agilis, utilizing cocoons of the primary parasitoid Cotesia glomerata as hosts in microcosm arenas consisting of a single Petri dish or two dishes connected by a tube. The number of compartments in each dish was varied and provisioning of food and hosts was either temporally separated by 48h intervals (single-dish microcosms) or spatially separated (two-dish microcosm). In the two experimental designs batches of host cocoons were offered to G. agilis females and cocoon fate (emergence of an adult primary or hyperparasitoid, or precocious death) was recorded. In the single-dish arenas in which provisioning of cocoons and food were alternated every 48h, there were no consistent effects of arena complexity (i.e., the number of compartment in the dishes) on hyperparasitoid longevity and fecundity, or host survival. However, when food and hosts were spatially separated in two Petri dishes connected by a plastic tube, longevity and fecundity of G. agilis traits were reduced, and survival of C. glomerata increased, in particular, when the number of compartments was increased. Additional experiments in the two-dish arenas in which only food, only cocoons or nothing was offered, provided further evidence that finding food is a major factor limiting longevity and, concomitantly, fecundity of the hyperparasitoids in more complex environments. Our findings are discussed within the contexts of habitat heterogeneity and resource-consumer interactions, and refuge theory.
README: Petri dish effect of hyperparasitoids
Female hyperparasitoid (Gelis agilis) that had been allowed to host feed for 48 h were released in one of the arenas (one female per dish) with four cocoons (Cotesia glomerata) and or honey+water for 48h periods. The number of compartments in a dish (13.5 cm diameter) was varied. Cocoons and or honey+water were replaced every 48h. Cocoons were stored in vials and their fate was recorded (adult hyperparasitoid, adult primary parasitoids, or dead cocoon when nothing emerged within a month since exposure to the hyperparasitoid).
Experiment 1----Single dish experiment alternating cocoons and food every 48h
Provisioning of cocoons and honey + plus water were alternated every 48h until the female died. Thus, females had access to only hosts for 48h, followed by access to only carbohydrates + water for 48h. This protocol was repeated until death of the female
Single dish arenas with a single compartment, 2, 4, 8 or 16 compartments
Data are stored in data sheet: Exp_1.csv
Variables in data sheets
Mother_ID unique identification number of the female hyperparasitoid released in the arena
Compartment number of compartments in dish=complexity variable in analysis
Rep replication number (10 or 30 replicates per arena type)
Total_cocoon total number of cocoons offered in a dish throughout the life of a female
Sum_G_agilis total number cocoons producing adult G. agilis offspring
Sum_C_glomerata total number cocoons producing adult C. glomerata offspring
Sum_dead total number of cocoons that were recorded as dead
Mother_longevity longevity of the female mother
Experiment 2.1---Two dish experiment offering cocoons in one dish and food in the other
Cocoons were offered in one dish and honey+plus in the other. Dishes were connected by a tube. Cocoons and food were replaced every 48h until the female died. This protocol was repeated until death of the female mother. Thus females had access to hosts and carbohydrates+water continuously, but had to travel from one dish to the other through the connecting tube.
Two dish experiment connected by a tube
Data are stored in data sheet: Exp2_1.csv
Experiment 2.2 as experiment 2.1 but here only carbohydrates+plus water were offered in one of the dishes until the female died.
Data are stored in data aheet: Exp2_2.csv
Experiment 2.3 and 2.4
Same arenas as in 2.1 and 2.2 but now females are provided with only cocoons placed in one of the dishes (2.3) or nothing at all (2.4). Longevity of the females was recorded, and data were combined into one data file Exp2_3_and_2_4 with the ‘exp’-column referring to the two experiments