Most bee flies (Family Bombyliidae) are parasites. They feed externally on the larvae of bees and wasps, consuming the host when it is in a ‘quiescent stage such as the mature larva, prepupa or pupa’ (1). Some are even hyperparasites, which means that – in the larval stage – they feed on other parasites, themselves feeding on the larval stage of another insect. The adults generally feed on nectar and pollen and may play an important role as pollinators.
I have come across this fly a number of times in northern Thailand, when trying to take photographs of butterflies. It is quite large (well over 1 cm in length) and commonly rests on the ground, often near water. I am fairly sure that it is Ligyra tantalus Fabricius, 1794, which has a very wide distribution, including China, Taiwan, India, Malaya, the Philippines and Thailand.
There is a reference in an Indonesia text to Ligyra tantalus being a parasite of wasp larvae of a Campsomeris sp., which are large Scoliid wasps (2). This suggests that it might be a hyperparasite, since another Ligyra bee fly species, Ligyra satyrus, larvae are found inside cocoons of a scoliid wasp, Campsomeris tasmaniensis Saussure, which are external parasites of canegrubs (Coleoptera: Scarabaeidae) (3). So if it is a hyperparasite like L. satyrus, L. tantalus would be classed as a pest, if it were feeding on the natural enemies of a plant pest!
This photograph was taken in February in Doi Sutep-Pui NP, Chiang Mai, Thailand.
1) Yeates, David K., and David Greathead. “The evolutionary pattern of host use in the Bombyliidae (Diptera): a diverse family of parasitoid flies.” Biological Journal of the Linnean Society 60.2 (1997): 149-185.
2) Hama penyakit tanaman. http://books.google.co.uk/books?id=IHkTEjTjTkcC&dq=Ligyra+tantalus&source=gbs_navlinks_s
3) Yeates, David K., David P. Logan, and Christine Lambkin. “Immature stages of the bee fly Ligyra satyrus (F.)(Diptera: Bombyliidae): a hyperparasitoid of canegrubs (Coleoptera: Scarabaeidae).” Australian journal of entomology38.4 (1999): 300-304.
This lovely little dove is endemic to the Galápagos islands, Ecuador. It is not know exactly how many there are on these islands, but it is not thought to be threatened. It does however, suffer from predation by introduced, feral cats. These cats are a real threat to some species on the Galápagos islands and need to be eradicated – otherwise unique species such as these will the threatened in the future.
This huge toad, Rhinella schneideri – over 20 cm in length – lives in South America: throughout North and Central Argentina, central Bolivia, the Atlantic coast of Brazil, Paraguay and Uruguay (1). It occurs in a wide variety of habitats, from urban areas to the Chaco, Cerrado and Atlantic Forest regions. Fortunately, it is not threatened – listed as being of Least Concern by the IUCN – and is common throughout its range; it is said to adapt well to anthropogenic disturbance, which perhaps explains why it is increasing in numbers, and bodes well for its future. (2)
It is called the Cururu Toad, or the Rococo Toad. Cururu is a river in the Pará state of north-central Brazil; presumably a lot of these toads live there! Rococo is however, a very good alternative name for this toad; the word was derived from the French word “rocaille”, which means pebbles and refers to the stones and shells use to decorate the interiors of caves. The toad looks very much like it is covered with small pebbles.
It is not too fussy about what it eats, as long as it is insect-like and crunchy! Beetles, insect larvae and ants are the mainstay of its diet, but it has even been seen swallowing bees at hives, so bee-keepers consider it a pest! (1)
Don’t try eating this toad! It has poison glands on its back legs, as well as on either side of its head, which can squirt a poison, which causes eyes or mucous membranes to burn painfully. According to one report, ‘a dog that has taken such a toad in its mouth will immediately and yowling release it’! (3) But the interesting thing is that some of the complex organic compounds found in the skin secretions from this toad – at least 10 different compounds have been isolated – are highly active against human cancer cells (4). So who knows, perhaps it contains a cure for cancer?
I took these photographs in March 2012, at a ranch in Corrientes Province, northern Argentina. The frog was obviously feeding on insects attracted to the lights on the buildings at night. I did not notice it at the time, but there is a red and white beetle on the back of the toad. What is it doing? In may be a prey item that just made a lucky escape, or perhaps there is some other sort of relationship occurring? Is it feeding on something on the toad? Who knows? There is also a mosquito feeding on the toad (just behind the right eye), sucking the blood no doubt – see below.
This blog has reminded me once again, that once you start looking closely at an animal, all sorts of interesting – and sometimes unexplained things – pop up!
2) Lucy Aquino, Steffen Reichle, Guarino Colli, Norman Scott, Esteban Lavilla, Jose Langone 2004. Rhinella schneideri. The IUCN Red List of Threatened Species. Version 2014.3. http://www.iucnredlist.org/details/54755/0
The Dusky Diadem [Ethope himachala (Moore, 1857)] is a fairly common species in upland regions of northeastern India, for example in provinces such as Arunachul Pradesh, Meghalaya and Nagaland (1). It has a Himalayan distribution which stretches from Sikkim, through NE India and Myanmar, down into northern Thailand. It typically occupies evergreen forest, where it can be seen basking or flying along forest streams (2). I can across this species whilst walking along a road near Sessa in Arunachul Pradesh, NE India.
Perhaps the most striking thing about this butterfly are its blue eyes. Eye colour is variable in butterflies; they can have brown, black, green, yellow, red, blue and probably many more colours besides (together with eye patterns or spots). Eye colour has been used to distinguish closely related butterfly species, but it can be misleading when examining museum specimens, since the eye colours fade with time after death (3).
Butterflies have very good eye-sight and are thought to see in colour (4). They are so brightly coloured and patterned – iridescent in many species – they must be able to see in colour, although exactly how the perceive the world (and each other), it is not possible to know for sure. It is difficult to say why a given species of butterfly has eyes of a certain colour; it may be related to a number of different factors. The so-called screening pigments in the pigment cells are said to generally determine the eye colour in insects. In butterflies however, there is also a structure called a tapetum – composed of highly folded tracheoles, or breathing tubes – which acts as a sort of reflection filter, improving the sensitivity of the eye and determining the colour, or ‘eye shine’ (4). So in nymphalid butterflies such as this, the blue colour is not due to the blue absorbing visual pigments (called opsins) in the eyes, but instead is caused by the colour of the light reflected by this structure which is at the back of the eye. Nevertheless, the blue colour is very striking against the dark umber-brown wings of the insect, and it is hard to believe that it does not somehow play a part in the behaviour of the butterfly. Perhaps males with the bluest eyes are chosen by the females? A nice idea but pure speculation!
On a historic note, The Dusky Diadem was one of many Indian butterflies first described by a Victorian entomologist called Fredric Moore (Moore, 1857). He worked for the British East India Company as an Assistant Curator, located in London at the East India Museum (housed in an extension to the East India House). Moore was largely responsible for a large, 10 volume work on the butterflies of the Indian region called Lepidoptera Indica (5). In the preface to these volumes, he described the work as being produced by “contributions….from numerous friends and correspondents who held or are now holding positions in the Civil and Military service in various parts of India”. In other words, he did not collect the butterflies himself, but rather described and catalogued the specimens sent in by a host of people scattered across British India at the time. The list of contributors included a remarkable cross-section of expatriate Englishmen (and they were all men, apart from one lady, a Mrs. F. A. de Roepstorff, although it seems that her husband – a superintendent of the Danish settlement at Camorta – collected the butterflies in the Andaman and Nicobar Islands ) employed in the service of the British Raj. They are all listed in the preface, and include a number of Captains, a Major, a Colonel, a Major-General, a number of Doctors, a Reverend and Knight of the Realm (Sir Walter Elliot who provided specimens and notes from Madras). It is fascinating, at least to me (!), to think of all these colonialists, engaged in collecting moths and butterflies as they went about their varied duties on behalf of Queen and country!
The males are slightly smaller than the females, with darker wings. The two sexes can be compared on Plate 54 of Volume 1 of Lepidoptera Indica (5). The volume has been digitized by the Internet Archive with funding from the University of Illinois Urbana-Champaign (6). It is wonderful that these old, highly valuable volumes are available for free online. It is worth looking at for the plates alone, most of which were illustrated by Fredric Moore’s son, F. C. Moore, who was clearly a highly talented artist. The Moore’s must have loved their butterflies, but I find it a bit sad that they did not see them flying around in the wild – I assume this was the case as there is no mention of them visiting India – and they based their vast study on pinned specimens sent back from India. This may explain why there was no mention of this butterflies blue eyes! There are also no blue eyes shown in the illustrations; just brown eyes which was presumably the colour of the faded specimens. No-one had digital cameras either in 1857! I am so glad to live in the present, with all the wonderful technology we have to hand.
Speckled Wood butterflies, Pararge aegeria, come in a variety of shapes and colours. Perhaps the most interesting thing about this species, is that it varies along a huge gradient (called a cline) from north to south, in Europe. In northern Europe (including parts of the UK), there is a darker subspecies (called P. a. tircis) whilst in southern Europe, a lighter coloured subspecies, called P. a. aegeria, is found. These two subspecies gradually change from one form to the other along a continuous gradient (ecocline).
Below is a picture of a Speckled Wood taken in England (in Bedfordshire) on 12 September (2014). The timing is important for this species, since Speckled Woods seen in late summer tend to be darker than those that emerge earlier in the year, e.g. during the Spring. This seasonal plasticity, as it is called, is probably as a result of differences in the growth and development of the butterflies at different times of the year, i.e. under different photoperiods and temperatures (1). In a similar way, there are phenotypic differences (in the expression of the same genome) between different landscapes in any given region. This species has recently colonised agricultural landscapes, where both males and females were found to be heavier, and better fliers than their cousins inhabiting nearby woodlands (2). It is this ability to adapt which has made this species one of the few recent success stories in terms of butterfly numbers. As well as expanding its range into more open habitats – including gardens, hedgerows and open grassland, the Speckled Wood is also extending it’s range northward in response to climate change (3)
We are lucky to have two additional subspecies in the UK: the Scottish Speckled Wood (P. a. oblita), and the Isles of Scilly Speckled Wood (P. a. insula).
The southern form of the Speckled Wood (P. aegeria subsp. aegeria) looks quite different from the northern one, with patches of orange – rather than cream on dark brown – on the upper sides of the wings, as shown below.
The southern forms of the Speckled Wood (i.e. Pararge aegeria ssp aegeria) also seem to me to be fairly variable in terms of the colour and brightness of the orange and brown parts of the wing, although some of this variation can be explained by factors such as the intensity of the sunlight and the age (degree of wear and tear) of the butterfly. This one (below) was also taken in northwest Spain (Galicia), but much earlier in the year – 14th Feb 2012 – than the more ‘orangey’ specimen seen above. N.B. some of the tones get altered slightly during processing! Nevertheless, based on the evidence of one photograph (!), darker individuals of the southern species may be appearing earlier in the year, the reverse of the situation for the northern form in the UK (see above). Something that needs more observations!
Finally, I have one more shot of the more ‘orangey’ type of P. aegeria ssp aegeria from NW Spain (Galicia), this time taken on 2 June 2011, showing a colour pattern very similar to the other one (above but one) I manage to photograph in June in a different year.
DNA studies have shown that the Speckled Wood – and sister species – originated from North Africa but do not easily cross the Mediterranean (4).
1) NYLIN, SÖREN, PER‐OLOF WICKMAN, and CHRISTER WIKLUND (1989). Seasonal plasticity in growth and development of the speckled wood butterfly, Pararge aegeria (Satyrinae).”Biological Journal of the Linnean Society 38(2), 155-171.
2) Merckx, T. and Van Dyck, H. 2006. Landscape structure and phenotypic plasticity in
flight morphology in the butterfly Pararge aegeria . / Oikos 113: 226/232.
3) Hill, Jane K., Chris D. Thomas, and Brian Huntley. “Climate and habitat availability determine 20th century changes in a butterfly’s range margin.”Proceedings of the Royal Society of London. Series B: Biological Sciences266.1425 (1999): 1197-1206.
4) Weingarter, Wahlberg & Nylin (2006): Speciation in Pararge (Satyrinae: Nymphalidae) butterflies – North Africa is the source of ancestral populations of all Pararge species. Systematic Entomology31: 621-632.
Butterflies in the genus Acraea – such as the Acraea Elegant, Acraea egina, feed selectively on plants with cyanoglycosides (poisons!) belonging to plant families such as the Passifloraceae (the Passion Flower family). So they are brightly coloured to advertise that they are poisonous, or at least distasteful to birds and other predators; and as such they serve as ‘models’ and are ‘copied’ in apearance by other butterflies which are not poisonous, i.e. Batesian mimics. An evolutionary strategy to benefit from another species without having to go through the process of eating all those nasty poisons oneself! Acraea egina is mimicked very closely by another nymphalid, called Boisduval’s False Acraea, Pseudacraea boisduvali, and by a swallowtail, Papilio ridleyanus!
Butterflies in the genus Acraea engage in what has been called by an Victorian lepidopterist, Marshall 1902 (Eltringham 1912), “marriage by capture”, to describe the fact that the males seize the females in the air. A remarkably detailed description of this process was described by Ward (1995) (2).
“The male Acraea (Acraea) acara approached the female at speed from behind and slightly to one side. The female was flying in a leisurely fashion up the slope of a grassy hill. The male attacked the female much as a raptor would attack its prey in flight. The male hit the female at full speed with his legs, striking her on the side of the body at the base of the hindwing underside. The female was grasped tightly by the male preventing her from flying and the pair spiralled to the ground. The male held the female tightly to the ground with her head pressed into the base of a tuft of grass. The male then curved his abdomen around until he managed, with difficulty, to engage his genitalia with that of the female. Almost instantly on penetration the male became comatose and slowly, with wings folded, fell sideways to the ground.
The female extricated herself from beneath the male and out of the tuft of grass. After a brief breather she flew away with her mate hanging down behind.”
Amazing stuff you come across in entomological journals!
Confusingly, Acraea egina is itself a mimic of sorts – a Müllerian mimic of Acraea zetes – which together with a number (about seven) of other butterfly species, forms what has been called a mimicry ring. The unpalatable species in the ring resemble each and converge to present a common pattern to predators, so that if say a bird learns by experience to avoid one species in the group, they all benefit from the fact that they look closely like that species.
It’s all very confusing and I am starting to wonder whether I have got the model or the mimic (or one of its friends!)!.
1) ELTRINGHAM, H ., 1912. A monograph of the African species of the
Genus Acraea Fab. Trans. ent. Soc. London 1.
2) Ward, Peter (1995). “180 METAMORPHOSIS, VOL. 6, No. 4 December 1995. LEPIDOPTERISTS’SOCIETY OF SOUTHERN AFRICA: 180.
In my experience, the Marsh Fritillary, Euphydryas aurinia, is relatively common in Galicia (NW Spain) – where I took these photographs – but is considered to be threatened in the UK, where it has declined markedly in recent years, particularly over much of eastern England and Scotland (1). Despite that, the UK and Spain are considered to constitute strongholds for this species in Europe. It is said to prefer damp heathy grasslands, but can be found wherever the preferred larval food plant – Devil’s-bit scabious – occurs. It tends to occur in a series of small habitat patches less than 2 ha in size – which constitute a series of metapopulations. These small subpopulations fluctuate – i.e. die out and reform – from year to year, but the overall metapopulation usually persists. If colonies become too isolated however, as a result of changes in farming practices (agricultural intensification and loss of hedge rows) for example, then the overall population is in danger of dying out. The metapopulation becomes too fragmented and isolated to withstand the vagaries of environmental variability (and parasitism), and cannot persist in the long run. But the exact size and number of meta-patches needed to sustain a population are not known precisely and probably differ from place to place. Grazing by cattle and horses is said to promote an open and uneven sward of grass, which favours the host plant and hence the butterfly. This might be one reason why Galicia in Spain appears to be such a good habitat for this species, as there are many small, naturally managed farms and small holdings with horses and cattle present. In more central parts of Spain, large numbers of this butterfly are favoured by traditional agriculture and extensive grazing by cattle and goats (2).
Marsh fritillary larvae feed on Devil’s bit scabious (Succisa pratensis) and a variety of of other plants, depending on habitat and subspecies, including Small scabious (Scabiosa colombaria), Field scabious (Knautia arvensis), teasels (Dipsacus spp.) and Gentians (G. punctata, G. lutea). In one spot – close to Cabo de Bares in Galicia – where there were quite a lot of Euphydryas aurinia butterflies flying around in mid-June, they seemed to be associated with Sheep’s bit scabious, Jasione montana. Certainly the adults were landing on and nectar-feeding from these flowers, although whether the larvae fed on them as host plants, I don’t know. I am tempted to think that they did, given the abundance of both butterflies and flowers of this species.
The Marsh Fritillary butterfly has a very widespread distribution, stretching right across the Old World from Ireland to China. It is a very variable species with at least 34 subspecies recorded across this region. Presumably, there are healthy populations in many different places in Asia where traditional agricultural practices result in the maintainance of habitats suitable for this butterfly. Nevertheless, even in regions such as the Iberian Peninsula where it is doing reasonable well, changes resulting in a more ‘fragmented and monotonous landscape’ threaten this and other species with local extinction (3). Conservation management has identified the particular mix of factors – such as sward height and stock grazing density – that encourage the persistence of this species in threatened sites. But traditional agriculture, with mixed farming and grazing by horses, cattle and goats, appear to maintain this species (and no doubt many other such as bumblebees and other butterflies) without the need for conservation management.
1) Dr Martin Gaywood. Scottish Natural Heritage Information and Advisory Note Number 9. http://www.snh.org.uk/publications/on-line/advisorynotes/9/9.htm
2) Munguira, Miguel L., et al. (1997). Use of space and resources in a Mediterranean population of the butterfly Euphydryas aurinia. Acta Oecologica 18(5), 597-612.
3) Junker, Marius, and Thomas Schmitt. “Demography, dispersal and movement pattern of Euphydryas aurinia (Lepidoptera: Nymphalidae) at the Iberian Peninsula: an alarming example in an increasingly fragmented landscape?.” Journal of insect conservation 14.3 (2010): 237-246.