README: Dataset associated with manuscript "Plasticity and associated epigenetic mechanisms play a role in thermal evolution during range expansion"

Due to global change many species are shifting their distribution and are thereby confronted with novel thermal conditions at the moving range edges. Especially during the initial phases of exposure to a new environment, it has been hypothesized that plasticity and associated epigenetic mechanisms enable species to cope with environmental change. We tested this idea by capitalizing on the well-documented southward range expansion of the damselfly Ischnura elegans from France into Spain where the species has invaded warmer regions in the 1950s in eastern Spain (old edge region) and in the 2010s in central Spain (new edge region). Using a common garden experiment at rearing temperatures matching the ancestral and invaded thermal regimes, we tested for evolutionary changes in (thermal plasticity in) larval life history and heat tolerance in these expansion zones. Through the use of de- and hypermethylating agents we tested whether epigenetic mechanisms play a role in enabling heat tolerance during expansion. We used the phenotype of the native sister species in Spain, I. graellsii, as proxy for the locally adapted phenotype. New edge populations converged towards the phenotype of the native species through plastic thermal responses in life history and heat tolerance while old edge populations (partly) constitutively evolved a faster life history and higher heat tolerance than the core populations, thereby matching the native species. Only the heat tolerance of new edge populations increased significantly when exposed to the hypermethylating agent. This suggests that the DNA methylation machinery is more amenable to perturbation at the new edge and shows it is able to play a role in achieving a higher heat tolerance. Our results show that both (evolved) plasticity as well as associated epigenetic mechanisms are initially important when facing new thermal regimes but that their importance diminishes with time.

Description of the Data and file structure

These datasets were used to assess the effect of temperature on life history and heat tolerance:

dataset_temperature_life_history.xlsx

• ID: ID of the larva
• temp: temperature at which the larva was reared (°Celsius)
• pop: population origin of the larva
• region: region origin of the larva
• mother: ID of the mother of the larva
• PopMother: combination of population and mother
• date_f0: day the larva reached the last larval stage (F0)
• sex: sex of the larva (m: male; f: female; NA: not available)
• mass_day2: mass in mg of the larva one day after reaching F0
• mass_day8: mass in mg of the larva 7 days after reaching F0
• seperation_date: data at which the individual was seperated into an individual cup
• development_time: days untill reaching F0

dataset_temperature_heat_tolerance.xlsx

• ID: ID of the larva
• temp: temperature at which the larva was reared (°Celsius)
• pop: population origin of the larva
• region: region origin of the larva
• mother: ID of the mother of the larva
• PopMother: combination of population and mother
• date_f0: day the larva reached the last larval stage (F0)
• sex: sex of the larva (m: male; f: female; NA: not available)
• treatment: the treatment allocation of the larva one day after reaching F0 (control: control conditions; zeb: zebularine treatment; 3-ab: 3-aminobenzamide treatment)
• mass_day2: mass in mg of the larva one day after reaching F0
• mass_day8: mass in mg of the larva 7 days after reaching F0
• CTmax: the temperature at which the larva become immobile during the CTmax experiment (°Celsius)
• Grid: the grid in which the larva was present during the CTmax experiment
• Machine_set: the machine set used for this larva during the CTmax experiment (three identical thermocyclers were used: A; B; C)

These datasets were used to assess the effect of the drug treatment on heat tolerance and global DNA methylation levels:

dataset_drug_treatment_heat_tolerance.xlsx

• ID: ID of the larva
• temp: temperature at which the larva was reared (°Celsius)
• pop: population origin of the larva
• region: region origin of the larva
• mother: ID of the mother of the larva
• PopMother: combination of population and mother
• date_f0: day the larva reached the last larval stage (F0)
• sex: sex of the larva (m: male; f: female; NA: not available)
• treatment: the treatment allocation of the larva one day after reaching F0 (control: control conditions; zeb: zebularine treatment; 3-ab: 3-aminobenzamide treatment)
• mass_day2: mass in mg of the larva one day after reaching F0
• mass_day8: mass in mg of the larva 7 days after reaching F0
• CTmax: the temperature at which the larva become immobile during the CTmax experiment (°Celsius)
• Grid: the grid in which the larva was present during the CTmax experiment
• Machine_set: the machine set used for this larva during the CTmax experiment (three identical thermocyclers were used: A; B; C)

dataset_drug_treatment_DNA_methylation_levels.xlsx

• 5MedCyd_concentration: Log10 of the 5MedCyd concentration in ul that was used as a proxy for the global methylation level of the larva
• pop: population origin of the larva
• mother: ID of the mother of the larva
• region: region origin of the larva
• treatment: the treatment allocation of the larva one day after reaching F0 (control: control conditions; zeb: zebularine treatment; 3-ab: 3-aminobenzamide treatment)
• sex: sex of the larva (m: male; f: female; NA: not available)
• CTmax: the temperature at which the larva become immobile during the CTmax experiment (°Celsius)
• extraction_method: DNA extraction method that was used to extract DNA (dna_kit: Qiagen's DNA extraction kit; dnarna_kit: Qiagen's DNA/RNA extraction kit). This DNA was afterwards used in the ELISA analysis

Sharing/access Information

Links to other publicly accessible locations of the data: none

Was data derived from another source? no