An obvious answer to this question would be - caterpillars.  But when did butterflies first appear?  There are now some 160,000 species of moths and butterflies -worldwide.  Seemingly, they appeared some 100 million years ago  - in North America.  They evolved from nocturnal moths in the period when flowering plants were undergoing a major expansion (in the Cretaceous period).  Butterflies may have become diurnal to avoid predation by bats, or it may have been to take advantage of nectar production and availability [using the proboscis]. The butterflies and their caterpillars were able exploit the diverse range of food resources that these ‘new’ plants offered.  Butterflies moved out from North America to South America and then on to other parts of the world, though they probably did not arrive in Europe until some 17 million years ago. The evolutionary expansion of the butterflies has been investigated by researchers at the University of Florida; they analysed the genetic makeup of many species (from 90 countries).  They were able to build up a picture of the relationships between the various groups of butterflies and also determined their evolutionary point of origin.  They also catalogued the plants eaten by the caterpillars and it was found that some two thirds of butterfly caterpillars feed on plants from the legume family (the Fabaceae - peas and beans).  It is probable that the first butterfly caterpillars also fed on these plants. Research at the Georgetown University in Washington DC suggests that larger species of butterfly are ‘coping’ better with higher temperatures, associated with global warming.  Bigger wings seem to offer a greater range of movement and the opportunity to find new and suitable habitats.  Smaller butterflies are not faring so well.  The study involved an analysis of the range of some 90 North American species between 1970 and 2010, during which period the monthly minimum temperature increased by 1.5oF. Others have analysed the butterfly collections at the Natural History Museum, using digital technology.   The Natural History Museum’s British and Irish butterfly (and moth) collection is probably the oldest, largest, and most diverse of its kind in the world; some of the specimens date back over a hundred years The measurements of the various specimens were paired with the temperature that the species would have experienced in its caterpillar stage. It was found that for several species that the adult butterfly size increased as the temperature increased (during late larval stage). So, it may be that we will see a gradual increase in butterfly size as temperatures increase with global warming. Join the Big Butterfly Count ? Between Friday 14th July and Sunday 6th August , the big butterfly count will take place.   For full details visit : https://bigbutterflycount.butterfly-conservation.org/about Thanks to Angus for images.

Butterfly Conservation has organised the Big Butterfly Count for the last twelve years.  This year, the count took place between 16th July and August 8th.  The count gives some information of how butterfly and moth populations are faring.  Both butterfly and moth numbers give us some information about the ‘health’ of our environment, and indeed what has been termed the insect apocalypse. Though some 150,000 counts were registered this year, the ‘average’ number of butterflies / moths recorded per count was nine. This was down from the average count of 11 last year,  and 16 in 2019.   The total number of butterflies / moths counted was down by some 14% overall compared to last year. Those species that had significantly reduced counts were Peacock down by 64% Common Blue down by 59% Speckled wood was down by 41% Small tortoiseshell and the Comma dropped by 32% On a more positive note, the ringlet and marbled white were recorded in greater numbers (but they did have low counts last year). The Spring weather was probably a significant factor in these generally disappointing results.  The wet May would not have helped breeding or feeding; low temperatures are not conducive to activity.  The poor weather would particularly impact on those species that normally produce two broads a year.   Further information on the results of the count can be found the Butterfly Conservation website :  here.

The first six months of 2017 were noteworthy for above average temperatures. Then July and August were characterised by unsettled weather and above average rainfall - indeed, it has been one of the wettest summers for a number of years. The effect of this weather was to reduce the number of butterflies seen during the Big Butterfly Count - which took place in late July and early August.  The ‘warmer’ early months of the year meant that the development of some butterfly species was accelerated so that their peak numbers occurred earlier than when the count took place.  Others were affected by the rather miserable ‘summer’ weather.  The count recorded the sightings of some 20 species of butterfly and moth. Read more...

The British have always been inclined to talk about the weather “it's been too hot, too cold, been raining for days etc”.  However, there is now some justification for discussing the weather as recent years have seen the number of extreme weather events increasing and there have been significant changes in the ‘pattern of the weather”. Though not extreme, the weather this Spring and early Summer has been been disappointing.  Sleet and snow fell in late April, and there were a number of sharp frosts.  The April temperature was 6.5o C, 0.9o C below the 20 year long term average.  Most regions were colder and wetter.  This pattern continued into June.  This sort of weather, when coupled with last year’s rather cold , wet summer has significant effects on both insect and bird populations. Read more...