DOI: 10.5061/dryad.7m0cfxpx6
title: Resource amount and discontinuity influence flight and reproduction in Hippodamia convergens (Coleoptera: Coccinellidae)

description: Industrial-scale agriculture creates a mosaic of large monocultures in the
 landscape, where seasonal cropping cycles generate discontinuous resource
 availability for insect predators both spatially and temporally. In this
 environment, selection will favor predator movement and reproductive
 behaviors that optimize the location and effective utilization of resource
 (prey) pulses that are both patchy and ephemeral in nature. Using a model
 system to study predator movement and reproduction, we tested how
 discontinuous periods of food resource access that mimic fluctuating
 resource populations (aphids) would influence flight behavior and
 reproduction of a highly mobile predator, Hippodamia convergens
 (convergent lady beetle), and possibly modify energetic trade-offs between
 these behaviors. Examining how these factors affect reproduction and
 movement in a lab context is an important first step toward understanding
 their corresponding performance in the field. Adult beetles were provided
 either short (3h) or long (6h) food pulses daily (continuous availability)
 or short (6h) or long (12h) food pulses every other day (discontinuous
 availability). We measured pre-oviposition period, fecundity, and
 fertility during an 18-day oviposition period, and female tethered flight
 activity (3h) before and after the oviposition period. We found that
 discontinuous food access delayed the onset of oviposition in the high
 food quantity treatment; fewer females laid eggs overall, and 18-d
 fecundity was lower compared to continuous provision of the same food
 quantity. A longer pre-oviposition period was associated with fewer
 reproductive days and lower fitness. Flight distance and fecundity were
 negatively correlated, suggesting that energetic expenditure in flight can
 deplete energetic reserves otherwise used for subsequent reproduction. The
 negative fitness effects of discontinuous resource access at fine temporal
 scales reveal how similar gaps in resource availability could influence
 lady beetle population dynamics and their ecosystem services within the
 agricultural landscape. Understanding how resource availability patterns
 affect lady beetle fitness and behavior can inform agricultural land
 management strategies to enhance their biological control services.
description: Reproductive data was collected by collecting and counting all
 eggs laid by participating lady beetle females on each day. Egg clutches
 were retained and hatch was also quantified. Flight data was collected
 using an automated infrared sensor with an Arduino and terminal program to
 collect and store tethered insect flight mill revolution data. The Flight
 output data was processed from the original text file output into an excel
 document and processed to remove extraneous lines and rows. Access was
 used to ensure ease of analysis and to allow for the use of queries. Raw
 data has then been processed to consist of lists of revolution time stamps
 rather than binary revolution/no revolution event data.
  
description: Microsoft Excel is required, Microsoft Access will be useful. All
 analysis was done in R studio.