Synchronisation of egg hatching of brown hairstreak (Thecla betulae) and budburst of blackthorn (Prunus spinosa) in a warmer future

Abstract

Synchronisation of the phenology of insect herbivores and their larval food plant is essential for the herbivores' fitness. The monophagous brown hairstreak (Thecla betulae) lays its eggs during summer, hibernates as an egg, and hatches in April or May in the Netherlands. Its main larval food plant blackthorn (Prunus spinosa) flowers in early spring, just before the leaves appear. As soon as the Blackthorn opens its buds, and this varies with spring temperatures, food becomes available for the brown hairstreak. However, the suitability of the leaves as food for the young caterpillars is expected to decrease rapidly. Therefore, the timing of egg hatch is an important factor for larval growth. This study evaluates food availability for brown hairstreak at different temperatures. Egg hatch and budburst were monitored from 2004 to 2008 at different sites in the Netherlands. Results showed ample food availability at all monitored temperatures and sites but the degree of synchrony varied strongly with spring temperatures. To further study the effect of temperature on synchronisation, an experiment using normal temperatures of a reference year (T) and temperatures of T ? 5°C was carried out in climate chambers. At T ? 5°C, both budburst and egg hatch took place about 20 days earlier and thus, on average, elevated temperature did not affect synchrony. However, the total period of budburst was 11 days longer, whereas the period of egg hatching was 3 days shorter. The implications for larval growth by the brown hairstreak under a warmer climate are considered.

Herbivore Larval Development at Low Springtime Temperatures: The Importance of Short Periods of Heating in the Field

“…They enable the larvae to develop at almost normal speed even at early springtime conditions in the field. Disadvantages, such as a possible (and possibly worsening) lack of synchronization of hatching with the availability of the host plants due to climate change [4,5], and slow development at temperatures close to the lower developmental threshold, are at least partly compensated for in the aforementioned ways. As long as the extreme values of thermal conditions are not too high to induce stress in the organisms [34], short periods of heating in the first place enable the exploitation of nutrient-rich food resources at this time of the year.…”

“…Asynchrony with plant phenology and factors that promote it, such as climate change, have a considerable impact on the dynamics of spring-feeding herbivores [4]. Synchronization between bud burst and egg hatch in a Lepidopteran species varies widely with spring temperatures, while an artificial elevation of temperature prolongs the total period of budburst but shortens the period of egg hatching [5].…”

Spring warming increases the abundance of an invasive specialist insect: links to phenology and life history

“…At a local scale, however, we found that although a 2 °C increase in mean air temperature significantly advanced the timing of C. ciliata revival and leaf emergence, their phenological synchrony was not disrupted. Maintenance of phenological synchrony has also been found in several other species interacting over trophic levels 38 , 39 . From these cases, we suggest that phenological asynchrony between insects and their host plants may not be a universal phenomenon under climate warming.…”

The seasonal sensitivity of brown bear denning phenology in response to climatic variability

“…In the last few decades, however, environmental conditions (e.g., weather and food availability) have varied greatly, especially under the ongoing climate change [ 9 , 10 ], which might have a negative effect on the functionality of the evolved biological time-keeping. Changes in phenology have been among the earliest observed ‘footprints’ of global climatic changes [ 11 – 13 ]. However, as most studies describing temporal shifts in phenological dynamics have usually ignored hibernation as a key phenological event for many species [ 14 ], our knowledge of whether and to what extent hibernation phenology is shifting in response to changing climatic conditions is limited [ 9 ].…”