Stonefly_EAG/README.md

Data sets and analysis scripts underlying the manuscript 'Reduced olfactory acuity in recently flightless insects suggests rapid regressive evolution'

Hypothesis

Insects have exceptionally fast smelling capabilities, and some can track the temporal structure of odour plumes at rates above 100 Hz. It has been hypothesized that this fast smelling capability is an adaptation for flying. We test this hypothesis by comparing the olfactory acuity of sympatric flighted versus flightless lineages within a wing-polymorphic stonefly species.

Data

We did electroantennogram recordings from sympatric wing-reduced and full-winged stoneflies. We always measured 4 stonefly antennae simultanously (2 full-winged and 2 wing-reduced). As stimuli, we presented a set of different odorants with varying valve opening durations. Each odorant - pulse duration combination was presented 10 times and we calculated the median response trace over the ten odorant pulses of the same type.

Dataset 1 & 01_Analysis_Dataset1.R

Dataset 1 contains the data for Fig 1, Fig 2, and Fig S1.

Median traces of electroantennogram recordings from wing-reduced and full-winged stoneflies from five different sampling locations in the South Island of New Zealand. As comparison, we also recorded honeybee antennae. Recordings with the photoionisation device (PID) show the dynamics of odorant concentration changes.

Dataset 2 & 02_Analysis_Dataset2.R

Dataset 2 contains the data for Fig S2.

To test whether the signal strength of live antennae is dependent on their physical properties, we utilized the negative signals in dead antennae induced by propionic acid (physical property) and compared them to the response strength to 2-heptanone (because this odorant induced the strongest responses) of the same antennae, but when still alive. Dataset 2 contains electroantennogram recordings of nine additional stonefly antennae. Each of the recorded antennae was recorded twice with the same stimulus protocol. In between the two protocols, the antennae were killed with hot water vapour.

Description of column headers

File: File name of the recording (rows with the same entry were recorded during the same experimental session; the first six digits indicate the year (20 = 2020), month and day of the recording session)

Channel: Recording channel (1 - 4)

Species: Animal species

Winged: Stonefly ecotype

Location: Sampling location (creek name for stoneflies or department for honey bees)

Odor: Odorant

PulseDuration: Valve opening duration during single pulses in ms

NumberOFPulses: Number of pulses used to calculated the median trace

Frequency: Rate (pulses/sec) of a pulse sequence (NA for a single pulse)

Sex: Sex of the animal

Antenna: Left or right antennae

ID: Identification number for each individual

AgeDays: Age of an individual in days after emergence

Config: Stimulus configuration file that determined the number and sequence of stimuli

Group: Indicates which data were compared.

Amplification: Amplification factor of the amplifier

AntennaState: State of the antenna (live or dead)

t1-t5000: Median voltage signal values. Note: the ampilification factors need to be considered to obtain the real amplitude of the signals.