Many tropical environments experience cyclical seasonal changes, frequently with pronounced wet and dry seasons, leading to a highly uneven temporal distribution of resources. Short‐lived animals inhabiting such environments often show season‐specific adaptations to cope with alternating selection pressures. African Bicyclus butterflies show strong seasonal polyphenism in a suite of phenotypic and life‐history traits, and their adults are thought to undergo reproductive diapause associated with the lack of available larval host plants during the dry season. Using 3 years of longitudinal field data for three species in Malawi, dissections demonstrated that one forest species reproduces continuously, whereas two savannah species undergo reproductive diapause in the dry season, either with or without pre‐diapause mating. Using additional data from field‐collected and museum samples, we then documented the same three mating strategies for a further 37 species. Phylogenetic analyses indicated that the ancestral state was a non‐diapausing forest species, and that habitat preference and mating strategy evolved in a correlated fashion. Bicyclus butterflies underwent rapid diversification during the Late Miocene, coinciding with expansions into more open savannah habitat. We conclude that the ability to undergo reproductive diapause was a key trait that facilitated colonization and eventual radiation into savannahs in the Late Miocene.

Phenotypic plasticity in heterogeneous environments can provide tight environment‐phenotype matching. However, the prerequisite is a reliable environmental cue(s) that enables organisms to use current environmental information to induce the development of a phenotype with high fitness in a forthcoming environment. Here, we quantify predictability in the timing of precipitation and temperature change to examine how this is associated with seasonal polyphenism in tropical Mycalesina butterflies. Seasonal precipitation in the tropics typically results in distinct selective environments, the wet and dry seasons, and changes in temperature can be a major environmental cue. We sampled communities of Mycalesina butterflies from two seasonal locations and one aseasonal location. Quantifying environmental predictability using wavelet analysis and Colwell's indices confirmed a strong periodicity of precipitation over a 12‐month period at both seasonal locations compared to the aseasonal one. However, temperature seasonality and periodicity differed between the two seasonal locations. We further show that: (a) most females from both seasonal locations synchronize their reproduction with the seasons by breeding in the wet season but arresting reproduction in the dry season. In contrast, all species breed throughout the year in the aseasonal location and (b) species from the seasonal locations, but not those from the aseasonal location, exhibited polyphenism in wing pattern traits (eyespot size). We conclude that seasonal precipitation and its predictability are primary factors shaping the evolution of polyphenism in Mycalesina butterflies, and populations or species secondarily evolve local adaptations for cue use that depend on the local variation in the environment.

New ecological niches that may arise due to climate change can trigger diversification, but their colonisation often requires adaptations in a suite of life-history traits. We test this hypothesis in species-rich Mycalesina butterflies that have undergone parallel radiations in Africa, Asia, and Madagascar. First, our ancestral state reconstruction of habitat preference, using c. 85% of extant species, revealed that early forest-linked lineages began to invade seasonal savannahs during the late Miocene-Pliocene. Second, rearing replicate pairs of forest and savannah species from the African and Malagasy radiation in a common garden experiment, and utilising published data from the Asian radiation, demonstrated that savannah species consistently develop faster, have smaller bodies, higher fecundity with an earlier investment in reproduction, and reduced longevity, compared to forest species across all three radiations. We argue that time-constraints for reproduction favoured the evolution of a faster pace-of-life in savannah species that facilitated their persistence in seasonal habitats.

http://www.eje.cz host-plant specialization will be an important determinant of traits involved in insect-plant interactions (Gripenberg et al., 2010, Schäpers et al., 2016.Oviposition preferences tend to be under strong selection in the wild because performance of larvae (Singer, 2004) and resulting adults (Scheirs et al., 2000) tends to vary greatly on the different species of plants on which the larvae develop. Indeed, experimental studies indicate a general congruence between oviposition preferences and larval performance (Thompson, 1988;Friberg & Wiklund, 2009;Gripenberg et al., 2010). However, oviposition preferences are not always strongly correlated with particular measures of larval performance, especially in host-plant generalists (Gripenberg et al., 2010). This is perhaps in part because host-plant generalists are under selection to make oviposition decisions that are adaptive over a wide range of host-plant species, and thus may use oviposition cues that are not optimal for each particular potential host. While more specialized dicotyledonous plant feeders often use particular chemicals that are characteristic of particu-

Author contributions: SH, PMB and OB designed the study; SH carried out the experiment;EvB and OB collected data for habitat preference; CJB wrote a custom ImageJ macro; OB made figure illustrations; SH and EvB carried out analyses and wrote the manuscript with inputs from CJB, PMB and OB. All authors read and approved the final version of the manuscript. 2 ABSTRACTGlobal change can trigger shifts in habitat stability and shape the evolution of organismal lifehistory strategies, with unstable habitats typically favouring a faster pace-of-life. We test this hypothesis in species-rich Mycalesina butterflies that have undergone parallel radiations in Africa, Asia, and Madagascar. First, our ancestral state reconstruction of habitat preference, using ~85% of extant species, revealed that early forest-linked lineages began to invade seasonal savannahs during the Late Miocene-Pliocene. Second, rearing replicate pairs of forest and savannah species from the African and Malagasy radiation in a common garden experiment, and utilising published data from the Asian radiation, demonstrated that savannah species consistently develop faster, have smaller bodies, higher fecundity with an earlier investment in reproduction, and reduced longevity, compared to forest species across all three radiations. We argue that time-constraints for reproduction favoured the evolution of a faster pace-of-life in savannah species that facilitated their persistence in seasonal habitats.

Information on the mating system of an insect species is necessary to gain insight into sexual selection and population structure. Male territoriality of the common evening brown butterfly Melanitis leda has been studied in the wild, but other aspects of its mating system remain largely unknown. For a population of M. leda in South India, we observed male-male and male-female interactions in captivity, measured mating duration and spermatophore mass, and also determined the degree of polyandry in the wild. We found that mating behavior takes place for short periods of time around dawn and dusk. Our observations corroborate that males compete in aerial combats (twirling) and interfere with mating pairs. In the morning, they may use shivering to warm up. Females can twirl with males and refuse mating by pointing their abdomens upwards or by flying away. Males court females by fluttering their wings while perched behind females, and then initiate copulation by curling their abdomens ca. 180 degrees sideways to make genital contact. While in the morning, matings lasted on average one hour and twenty-three minutes and never exceeded three hours, in the evening, matings could be of similar duration, but 42% of butterflies only separated when dawn was approaching. However, such long nocturnal matings did not result in heavier spermatophores. The first spermatophore of a male tended to be larger than subsequent spermatophores. Together with previous studies on this species, our findings suggest that males compete mainly through territorial defense (as reported before), courtship performance, and interference, and to a lesser extent by providing spermatophores, while females exert some control over the mating system by the timing of their receptivity and mate choice.

In variable environments, phenotypic plasticity can increase fitness by providing tight environment‐phenotype matching. However, adaptive plasticity is expected to evolve only when the future selective environment can be predicted based on the prevailing conditions. That is, the juvenile environment should be predictive of the adult environment (within‐generation plasticity) or the parental environment should be predictive of the offspring environment (transgenerational plasticity). Moreover, the environmental predictability can also shape transient responses such as stress response in an adaptive direction. Here, we test links between environmental predictability and the evolution of adaptive plasticity by combining time series analyses and a common garden experiment using temperature as a stressor in a temperate butterfly ( Melitaea cinxia ). Time series analyses revealed that across season fluctuations in temperature over 48 years are overall predictable. However, within the growing season, temperature fluctuations showed high heterogeneity across years with low autocorrelations and the timing of temperature peaks were asynchronous. Most life‐history traits showed strong within‐generation plasticity for temperature and traits such as body size and growth rate broke the temperature‐size rule. Evidence for transgenerational plasticity, however, was weak and detected for only two traits each in an adaptive and non‐adaptive direction. We suggest that the low predictability of temperature fluctuations within the growing season likely disfavors the evolution of adaptive transgenerational plasticity but instead favors strong within‐generation plasticity.

The Indian Elattoneura are a difficult group to identify due to their extreme morphological similarity and sparse information in identification keys and on geographical distribution. The ambiguity is prominent among two Peninsular Indian Elattoneura species, E. nigerrima (Laidlaw, 1917) and E. tetrica (Laidlaw, 1917), described a hundred years ago. Both species were described based on male specimens with scant information on their females. The species are IUCN Red-listed, E. nigerrima (Data Deficient) and E. tetrica (Least Concern). Hitherto it was thought that E. nigerrima was smaller than E. tetrica and both have non-overlapping geographical distribution. Here, we re-described both sexes of E. nigerrima; E. tetrica along with morphometric data and geospatial analysis. We found that E. nigerrima is significantly larger than E. tetrica. The species are largely allopatric in distribution, with the former having a much wider spatial distribution than previously thought. Based on our geospatial analysis, we provide occurrence data useful for the future IUCN assessments of E. nigerrima and E. tetrica. We highlight the importance of updating taxonomic status information and data on spatiotemporal distribution to proceed with the conservation of endemic insects such as Elattoneura damselflies. Our study indicates reassessments of Indian Odonata species are urgently needed.