Table 2.

Life-history traits used to predict butterfly's dispersal with generalized linear models. All traits are available for 142 butterfly species, except the laying strategy that is available for 137

Trait	Trait description
Fecundity	Mean number of eggs laid by females of the species (9 categories).
Adult lifetime	Mean duration (days) of the adult stage. Upper limit set at 60 days for species that overwinter as adults: ranges 5–60 days.
Voltinism	Annual number of generations, from 0.5 (biannual species) to 3 generation/year.
Larval growth rate	Duration (days) of the feeding period for larvae (i.e., without diapause), averaged over successive generations of a year; ranges 16–186 days.
Ripe egg load	Number of mature eggs in female's abdomen at emergence (9 levels).
Ovigeny index	Proportion of full-grown eggs at emergence (ranges 0–1).
Female maturation	Time (days) between female emergence and its first laying: 8 levels, from 1 (1–2 days) to 8 (laying starts after several weeks of diapause).
Overwintering stage	Stage at which the species usually overwinters. 8 categories: from 0 (egg) to 6 (adult), and an additional category for species without overwintering (warm regions).
Flexibility of life cycle	Separates on the one hand species with inflexible life cycle and on the other hand species with prolonged, shortened, or repeated diapause, with facultative estivation, or with staggering of emergences, all considered ‘flexible species’.
Flight period	Length (in weeks) of flight period (averaged over successive generations where relevant); ranges 3–32 weeks. Results from the interplay between adult lifetime and the synchronization of adult emergences, as shown by a low but significant correlation with lifetime (correlation = 0.34, P < 0.001: Stevens et al. 2012).
Thermal tolerance	Degree of adult tolerance to temperature extremes and temperature variation (9 levels).
Adult habitat range	Number of different ecosystems in which adults of the species are usually found (ranges 1–7).
Larval dietary breadth	Number of different host plants caterpillars of the species accept: 4 levels: 1 = plants of one species, 2 = plants of one genus, 3 = plants of several genus of the same family, 4 = plants or several families.
Myrmecophily	Degree of association with ants, from 0 (no association at all) to 9 (obligate, long association).
Female precision	Female precision in egg-laying, 9 levels: from 1 (the female lay where it lands, or even flying) to 9: the female choose the exact position (plant species, plant tissue, height, and orientation) before laying each egg or batch of eggs.
Laying strategy	Female egg-laying strategy: segregates single-egg layers from those species that lay batches of ≥ 2 eggs.
Mate location	Seven levels in the strategy of males mate location, from 1 = sit-and-wait strategy to 7 = strong lek forming, through 3 = patrolling and 5 = territoriality, and intermediates.