Friday, 17 February 2017

Gran Canaria & Fuerteventura - Nymphalidae (3)

Danaus plexippus
This nearctic species is fairly common in the Canary islands, reproduction probably happens mostly near urban environments where the larval foodplants of the genera Asclepias and Gomphocarpus are widely used in gardens and parks but as it is a strong flyer you can come across a Monarch about every where there are some flowers and trees.

nectar feeding on the larval foodplant Asclepias curassavica

males are recognized by their androconial patches central on the hindwing

Danaus chrysippus
This species is more confined to natural habitats in the Canaries than previous species. It is an afrotropical species with a migratory behavior, each year moving up north to the Mediterranean area with highest abundances in autumn. Most probably the species can't survive Mediterranean winters. 
In the Canary islands this species is probably present year-round and is mainly found in warm barrancos, these locations heat up quickly during the day but still hold some humidity in the lowest parts creating the specific needs for this species with the larval foodplants present on the dry slopes and more lush vegetation with nectar for the adults.



Vanessa vulcania
This Macaronesian endemic can be found on Gran Canaria & Fuerteventura. I only saw a few individuals on Gran Canaria, it seemed less common than on Tenerife last year.



Vanessa atalanta
Seen more or less daily but never in great numbers.



Vanessa cardui
This species was common all over, mostly in singletons but near Betancuria in central Fuerteventura locally large numbers could be found. Most of these butterflies were rather fresh, suggesting that these butterflies were locally bred and not immigrants for more south. Larvae were found on lots of locations on at least three different foodplants: Malva cf. parviflora (GC & FU), Cynara cardunculus (FU) and Forsskaolea angustifolia (GC & FU). Apart from living larvae also lots of empty larval cases were found, some of them containing dried up dead larvae suggesting a high level of predation and/or parasitism.

nearly full grown larva on Malva

young larva on Cynara cardunculus 

Some Echium decaisnei plants near Betancuria attracted high numbers

nice & fresh

Vanessa virginiensis
In older literature this species is not mentioned for Gran Canaria, recently however there seem to be at least some sightings (see for example). I saw one individual in central Gran Canaria but unfortunately was unable to make pictures. Luckily I made some nice pictures last year.

Pararge xiphioides
Endemic to the 5 western islands, strangely enough I only saw one individual on Gran Canaria. As it was early in the trip I didn't put much effort in making pictures. Probably this species is more common in the more humid north of the island, while we mainly visited locations in the southern half of the island. Pictures of this species in last years overview.

Hipparchia tamadabae
Flight period for this species is mostly described as starting from april (late march). A picture on lepiforum suggested already that locally this species can fly more early. It was however not until we accidentally met some Belgian friends who had made pictures of an individual end of January that I started to hope to see this species this early. When returning to Gran Canaria from Fuerteventura we visited both the location of the Belgians as the location of the German observation and on both locations we saw the species. This must by far be the earliest Hipparchia to start flight season!









Thursday, 16 February 2017

Gran Canaria & Fuerteventura - Lycaenidae (2)

Cacyreus marshalli
This originally southern African species is well spread in the Canaries, mainly around buildings where the larval foodplant Pellargonium grows, but it can be found in more natural environment ass well. This species was accidentally introduced to the Balearics in the late 1980's and has since then spread all over the Mediterranean area. Nowadays it can be found from the Canary islands in the west to Turkey in the east.





Cyclyrius webbianus
This species is an endemic of the 5 westernmost Canary islands so it can be found on Gran Canaria but not on Fuerteventura/Lanzarote. The species is not uncommon in natural environments in Gran Canaria although numbers are rather low in winter. More information on this species in the post from last year.





Lampides boeticus
This is a subsaharan migratory species, just like the well known Vanessa cardui. Building up populations after winter, each generation moves up further north into Europe, retreating back south when northern winter starts again. This species is fairly common in the Canaries with locally nice numbers together. Probably the species breeds throughout the year in the Canary islands.




Leptotes pirithous
Just like previous species this is an African migratory species, however reaching less far north into Europe where populations never really reach far beyond the Mediterranean region. Unlike previous species this one is only recently known from the Canary islands, only since halfway the 1990's observations became known of the Canaries but now it has been seen from all of the islands already.



For people having difficulties in determination of Lampides boeticus and Leptotes pirithous this last picture can be an informative one. The lower individual is Leptotes pirithous, the other is Lampides boeticus
In Leptotes pirithous you can see a clear white line at the base of the front wing along the costa, in Lampides boeticus you can see broad vague white lines in between the fine white lines where Leptotes pirithous only has a chaotic pattern of fine white lines.


Polyommatus celina
This taxon replaces Polyommatus icarus in N-Africa and some extreme southwestern parts of Europe and has no definite external characters but differs clearly in mtDNA. In the two easternmost Canary islands it is present as well and not uncommon wherever the larval foodplant Lotus lancerottensis is present. There are records from some of the more westerly islands as well but these remain unconfirmed and may refer to misidentifications with other species of blues present.

male

Brightly coloured female on the larval foodplant

male

Aricia cramera
Present on the 5 westernmost Islands. It replaces Aricia agestis in the Iberian peninsula and northern Africa. We didn't see it last year on Tenerife or La Gomera but found it not uncommon on Gran Canaria this year on some semi-natural grasslands.

copula

male

Zizeeria knysna
Mostly on grasslands around human settlements but the male pictured here was found in a dried up barranco in semi-natural environment.



Azanus ubaldus
This is a desert species with a distribution from central Asia to N Africa. Until recently there were only a few sightings from the Canary islands, except from one Fuerteventura sighting all of them from the southern tip of Gran Canaria. Recently more about the life cycle became known.
It is a very small species flying at high speed through the branches of its larval foodplant, in Gran Canaria the non native Acacia farnesiana and Prosopis juliflora. After more than two hours of observations I saw the species on some 5 occasions, some of these probably concerning the same male doing patrol flights. Unfortunately I was not able to make pictures in the field because never I saw the species sitting down. With some mechanical help however I could confirm the species, as these same trees are used by Leptotes pirithous as well. The latter is however a slightly bit bigger and brighter blue and has a less erratic flight. Both confirmed larval foodplants are used as ornamental plant on the Canary islands, above that both species, and especially Acacia farnesiana, have a tendency to become invasive species. We saw lots of Acacia farnesiana in some abandoned fields along the GC-505 road just N of the main highway, unfortunately too late on the day to stop and have a check for Azanus ubaldus.

Acacia farnesiana

female Azanus ubaldus, released in situ

Wednesday, 15 February 2017

Gran Canaria & Fuerteventura - Introduction and Pieridae (1)

Last year I made a winter visit to Tenerife & La Gomera. This year again we wanted to enjoy some sun in winter time so we decided to pick two other of the Canary islands to travel to, we left Belgium on 26th of January and returned on the 7th of February. The island choice was easily made. The period is the ideal period to see some small Pierids on the eastern Islands and visiting Gran Canaria and Fuerteventura gives enough variation in habitats to make a twelve day stay enjoyable. Some basic information on the Canary islands can be found in this previous post. Here I will start immediately with species accounts of the species seen on this trip.

Whites - Pieridae

Pieris rapae & Colias croceus were of the most common butterflies observed all over. As they are part of the most common butterflies in Europe as well, I will not go deeper into the observations made of these species. The same for Pontia daplidice, this species can be very common in SW Europe and can be encountered all over the Canary islands, although in winter it doesn't seem to be the most widespread species.

Euchloe (Elphinstonia) charlonia
This small sulfur yellow butterfly has a distribution all over northern Africa and parts of the Middle East. In southern Turkey the distribution reaches the distribution of the look-a-like Euchloe penia. To the west the species reaches the two easternmost Canary islands Fuerteventura & Lanzarote. Some populations on mainland Spain, only discovered in the 1990's, are nowadays considered a species on its own, Euchloe bazae. There are observations of E. charlonia in more or less all months of the year but at least in the Canary islands main flight period seems to be limited to late winter - early spring, from December to April, in one main and a second partial generation. The species is a strong flyer and can be seen almost everywhere in open landscape. Males can most easily be found by their hill-topping behavior, females can probably more easily be found in the slightly more humid corners of the barrancos in this barren landscape as these are the locations where several Brassicaceae grow that serve as larval foodplant. Most butterflies we saw were already a bit abraded, probably we were over the peak of the first generation.




Euchloe hesperidum
The Canary islands holds some butterfly taxa closely related to Euchloe belemia, widespread in the southern Iberian peninsula and N-Africa with representatives on 3 Canarian islands (FU, GC and TE). Recent genetic research shows these representatives to be genetically distant from the mainland populations and shows a considerable amount of genetic distance between these three island populations as well. As a consequence these three taxa are considered on Fauna Europaea as three different species.
In Fuerteventura, E. hesperidum is a fairly common species to be found all over the islands in the slightly more humid corners of barrancos, along abandoned fields and road verges.



Euchloe grancanariensis
This is the representative of the Euchloe belemia group on Gran Canaria. We found it fairly common higher up in the mountain, as with other species of this genus the hill topping behavior of the males makes it not to difficult to find the species.




Catopsilia florella
This is a species with mainly a tropical African and Asian distribution and with a well known migratory behavior. Thanks to this behavior and the fact that the non native larval foodplant is being used in the Canary islands as an ornamental plant this species has been able to build op some local populations on the Canary islands, mainly to be found in tourist resorts and coastal towns where the conspicuous foodplant Cassia (=Senna) didymobotrya grows in gardens and parks. We found the species at the entrance of the Oasis park in Fuerteventura. As well a full grown caterpillar on the foodplant as a few recently emerged adults.




More on Lycaenids in the next thread.


Wednesday, 16 November 2016

Orange Hesperids in NW-Europe

When browsing through all sorts of citizen science pages collecting nature observation data I notice there is still a lot of confusion about the determination of some widespread orange Hesperids in at least NW-Europe but definitely also outside that area.
Recently, together with some marvelous butterfly scientists, I could publish a paper concerning this matter, especially about the consequences of these difficulties in determination for the conservation of these butterflies. The article can be found here, anyone interested in more information can contact me: https://link.springer.com/article/10.1007/s10841-016-9924-4
But of course, these kind of articles are not the right location to put more information on the field determination criteria as only few of the involved citizen scientists read the scientific literature on butterflies.
For this reason I wanted to repeat some information on my blog. Some of you may think that this is not really necessary anymore with new butterfly field guides still appearing every now and then. Well, then have a good look on this page, scanned from the recent "Papillons de France" book (2014). Although the pale spots are nearly invisible on the picture the hooked tips of the antennae leave no doubt that the individual on the right upper side doesn't show a Thymelicus lineola but an Ochlodes sylvanus!!!


Although I believe that the author, T. Lafranchis, achieved a lot with his books on European butterfly determination - making butterfly determination accessible for many thousands of people - as well as with his publications on butterfly ecology, such mistakes may eventually lead to large uncertainties in distribution databases (strikingly the distribution map shows T. lineola to be absent in the very NW of France while in fact in adjacent parts of Belgium it is the most common Thymelicus!) making it impossible to investigate what conservation measures should be taken to help certain species.
I will talk about 5 species only in this thread, although there are some more orange coloured skippers in the WP area, some of them are confined to far away regions where citizen science is still not the major means to collect distribution data (Thymelicus hamzaThymelicus hyraxThymelicus novumOchlodes hyrcana) or where no other species is present that can cause confusion (Thymelicus christi).

Thymelicus lineola
This small species is common in large parts of Europe, an increase in distribution has been noted in UK, Belgium & the Netherlands some time ago but recently at least in the Netherlands (and most probably in Belgium as well but in Belgium there is a lack of standardised monitoring) a decrease in abundance has been noted.

This fresh male shows the golden orange colour of the upperside. The black border on the wing diffuses to some extent in the veins. The androconial stripe is short and straight, in fresh males you can see that it consists of two parts with a very short stripe extra near the wing base.


The underside of the antennal club is black. Care should be taken however in abraded specimens late in the season, where this colour can fade to brown making confusion with T. sylvestris to become a big pitfall. In very abraded specimens it can therefore be advisable to keep the determination on Thymelicus species (although analysis from the genitalia in those cases will always give away the true identity but this is work for specialists).


The underside is straw coloured, sometimes with a grayish or even a greenish hue, underside colour however should only be used as indicative and not as discriminating character (see T. sylvestris).



Thymelicus sylvestris
Much alike previous species but there are some differences. A common species in large parts of Europe. At least in Flanders - and in the Netherlands as well - this species seems to suffer and decreases have been noted, as well in distribution as in abundance.

The main feature from previous species is the underside colour of the antennal club. This is brownish to orange. This feature is best to be seen in front view, evaluating this feature from the upperside will eventually lead to wrong interpretations.


The androconial stripe is slender but long and curved, fresh males can mostly be recognised by this. The black hind border is a bit more demarcated.


The underside of the hindwing and underside of frontwing tip mostly have a greenish hue and sometimes this is described as a feature to T. lineola where the underside more has a yellowish straw colour creating a less clear contrast between the colour of the base of underside frontwing with the wingtip. I strongly advise not to use this as a discriminating feature. Although the trend is certainly there, the colour of the underside is variable to some extent with some T. lineola having a bigger contrast and some T. sylvestris not showing much of the contrast. Apart from that, interpretation of colours and such contrasts from pictures is very dependent on lightning circumstances and camera settings. A good example of a picture showing T. lineola with a nice contrast between frontwing tip and base can be found here.



Thymelicus acteon
This is the rarest Thymelicus species in NW Europe. A lot of people claiming to have seen this species refer to the very small size and indeed this is the smallest of NW European orange skippers. However, the small size on itself can never be enough to conclude for this species! Male forewing length is described as being 11-13mm in Higgins & Riley for T. acteon while in T. lineola male forewing length is 12-14mm, so this means an overlap op 50% in males! When we then take into account that females normally are a bit bigger than males it is not so uncommon for an individual of T. lineola to be smaller than a T. acteon!
As in T. sylvestris the underside of the antennal club is orange. The underside of the wings is unicolourous orange-like, sometimes a bit more grayish.
When suspecting to see this species, one should really try to get a view on the upperside as there the best clues are to be found. The ground colour of the upperside is clearly more brownish than orange, unlike previous two species, lacking the golden hue.

A male T. acteon clearly showing a more brownish ground colour a long, slender and curved androconial stripe and showing the faint half circle of pale spots in the wingtip (pictured in Belgium by Wim Declercq, clicking on the picture brings you to the original location)


In females of course the androconial stripe is absent but the half circle of pale spots is more clear and can't be missed.


Ochlodes sylvanus
This is a common species in large parts of Europe, often found in conditions that are a bit humid, f.e. rather at a forest edge than on large steppe grasslands. The frontwing edge can sometimes be a bit concave and the wing is more pointed than in the Thymelicus genus. Pale spots are obvious on upperside frontwing and contrasting with the darker brownish outer edge. Androconial stripe in males are broad and long, there is a clear S-shaped curve in it, with the broadest point in the middle. The antennal club has a clear and long hook.



Pale spots are visible on the underside hindwing as well but in very fresh specimens can remarkably be far from obvious while in some abraded individuals the spots on the underside can remind of the next species.

A fresh (upper) and an older (lower) specimen

The underside of the antennal club has a black tip as well, like in T. lineola, but the hook should always be obvious.


Hesperia comma
This species is a bit more confined than several of the common previous species. In NW Europe it is mostly found on dry heathlands or large dune complexes. In central Europe it is found on large calcareous grasslands, poor mountain grasslands, large steppes,...
Like in previous species the antennal club is hooked, however the club itself is a bit shorter and thicker and the hook as well is shorter than in previous species.
The androconial stripe is more triangular - broad at the base and pointed to the wingtip - and less S-shaped as it is in Ochlodes sylvanus. Clearly visible in this picture by Robin Septor (again, clicking on the picture brings you to the original location)


The spots on the upperside are clearly visible and the two outermost spots are a bit more demarcated from the other spots, more than in Ochlodes sylvanus. As can be seen on this female.


Underside is greenish, sometimes with olive hue. On the underside hindwing as well, spots are clearly demarcated and the comma-shaped spot in the wingbase is what gave this species its name.

There is some variation in the size of the pale spots on the underside, this variation has led to description of some subspecies. In this Spanish individual the spots are bigger and the ground colour is faded to brown.