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:
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.

Thursday, 6 October 2016

Some Zygaenidae and Sesiidae seen in 2016

Just a short post showing some pics of day-active moths seen during trips this year


Rhagades pruni, male, Belgium
rather widespread on heathlands in the NE of Belgium, this picture however was made on a calcareous grassland in the very south of the country

Zygaena filipendulae, Belgium, the most common Zygaenid in Belgium

Zygaena transalpina, Belgium, notice the pale tips to the antennae
Rare species in Belgium, unclear to me if the few sightings are from migrants or if the species is just overlooked because of its resemblance with Z. filipendulae. The main character seems to be the pale tips to the antennae, although in some literature also the merging red spots on the underside frontwing is given as a character. However when looking at pictures of collected Zygaenids it seems to me like that character is variable in Z. filipendulae with some individuals showing merging red spots on the underside frontwing as well.

Zygaena fausta, Spain

Zygaena occitanica, Spain

Zygaena lavandulae, France

Zygaena sarpedon, France, unfortunately not easy to approach for some nice fieldpics

Zygaena loti, France


got some great help from Theo Garrevoet of the FES to find the species names of these ones

Pyropteron chrysidiformis, first one from Corsica, second one a darker individual from Vaucluse, France

Chamaesphecia aerifrons, Corsica

Pyropteron leucomelaena, Spain

Monday, 5 September 2016

Spain: 18th July - 4th August : Hesperids

Pyrgus alveus
Under this species a complex of closely related taxa is parked and some authors even give species rank to some of the described taxa, f.e. ssp. accretus or ssp. trebevicensis. For Spain ssp. centralhispaniae is described. Pictures are from Sierra de la Sagra, both pictures show the same individual.

Muschampia proto
This species can be found in the whole Mediterranean area. In southern areas of Spain it is common whenever the larval foodplant Phlomis species is present. Pictures are from Sierra Tejeda.

Carcharodus baeticus
A species with a western Mediterranean distribution, to be found near its larval foodplant Marrubium species. Pictures come from the east of the Sierra Nevada and show a territorial mail on a dry foodplant.

Gegenes nostrodamus
Unlike what some field guides suggest, determination of this species from the related Gegenes pumilio is not straightforward and in many cases is impossible in the field. Research of collected specimens have shown that the latter species however is most probably absent from the Iberian peninsula unlike what some distribution maps in several field guides suggest.

A territorial male from the Alpujarras

A female in the agricultural landscape NW of Tarifa

Borbo borbonica
Since long it was known that this species, with mainly an African distribution, was present in the very south of the Iberian peninsula. It is however only since recent that more is known about the distribution and phenology of the species in Spain, mainly through the work of Sariot:
Midsummer is not the best moment to search for the species, better is to look at the end of summer when the third generation flies. We decided to give it a try anyhow and found a few individuals. The reason why this species could keep itself out of sight of entomologists is probably because the habitat is only rarely visited by entomologists. It is most easily found in agricultural landscape, along artificial water flows where Ecballium species is numerous, this plant is a favorite nectar plant of the local populations of Borbo borbonica. The few individuals we saw where very active and difficult to approach.

Just flying up and in this way showing a glimpse of the large white spot on the upperside of the frontwing.

Nectar feeding on an Ecballium species

Spialia rosae
Recent genetic research suggested two genetic lineages in the Iberian populations of Spialia sertorius. Further research showed that the unknown lineage in fact had a different biology. They are found at higher elevations than the classic Spialia sertorius, they use a different foodplant (Sanguisorbum species in Spialia sertorius, Rosa species in the unknown lineage) and they had a different prevalence of Wolbachia infection (Wolbachia is a maternal inherited endosymbiotic bacteria that can have an influence on the mithochondrial variation of their host; in Spialia sertorius no Wolbachia infection is found while in the unknown lineage a 100% prevalence of Wolbachia infection seems to be the case). This lead the researchers to describe this lineage as a new species; Spialia rosae. Their findings have recently been published (9th july 2016 online): 

In the eastern part of the Sierra Nevada, in a small humid valley on 2150m, we saw several Spialia sertorius s.l. on a location with a lot of small Rosa plants. While following an abraded female it immediately was apparent that this female had a particular interest in the small Rosa plants and I could see the female ovipositing on the young leaves of this Rosa plants. I have never seen a species so soon after the species description!

Spialia rosae, territorial male

Freshly laid egg of Spialia rosae on Rosa species

Freshly laid egg (left under), freshly emerged larva (center up, starting to spin its larval nest) and empty egg scale (right middle, at the pinkish base of the branch) of Spialia rosae on Rosa species.

Detail of the egg of Spialia rosae on Rosa species.

Sunday, 4 September 2016

Spain: 18th July - 4th August : Nymphalids (Incl. Satyrids)

Argynnis adippe chlorodippe
The Iberian subspecies of Argynnis adippe is with its greenish wash on the underside very different of the nominate subspecies that is present in a large part of Europe. Here in Sierra de la Sagra but can be found in large parts of Iberia.

Brenthis hecate
We didn't expect to see this local species this late, early august in Sierra de Albarracin.

Euphydryas desfontainii/aurinia beckeri
In Serrania de Cuenca we found a nest of young caterpillars of an Euphydryas species. Help in determination is welcome. Larval foodplant is most probably Cephalaria leucantha (but I am no botanist).

Danaus plexippus
This species is mainly known from its nearctic distribution and its migratory behavior but since some time it has some sedentary populations in the southern coastal areas of the Iberian peninsula.

Pyronia cecilia
Relatively common in the southwest of Europe

Arethusana arethusa
We only saw the nominate in central Spain, need to go back to Andalucia late summer once to see the subspecies boabdil, sometimes considered a species on its own.

Erebia hispania
An endemic of the high slopes of the Sierra Nevada, common at the right height and location. The hard wind made the right front wing of this one being out of place, giving us a glimpse on its upperside. Pictures are from the western part of the Sierra Nevada at 2500m+.

Erebia zapateri
Endemic of the eastern part of Spain's central mountain system. Named after the Spanish late 19th century entomologist Bernardo Zapater. Fligth period is late in the season, mainly in august. In Sierra de Albarracin fairly common in open grassy areas in the pinewoods between 1450-1700m.

Coenonympha dorus
Not uncommon in mountainous areas throughout Spain. First picture from Sierra Tejeda, second picture from Serrania de Cuenca.

Coenonympha glycerion iphioides
Iberian form of Coenonympha glycerion, sometimes considered as a species on its own. Picture is from Sierra de Albarracin.

Coenonympha pamphilus lyllus
In most field guides lyllus is described as the southern summer form of Coenympha pamphilus, some literature however considers this as a species on its own. I am still interested if someone would have a digital copy of following article:
BOILLAT, H., 2003. Coenonympha lyllus Esper, 1805, spec. rev. une nouvelle approche taxinomique du complexe pamphilus. - Alexanor 22:243-309
The picture shows a female from Serrania de Cuenca.

Hipparchia statilinus
In the Mediterranean area this is a common species, in northern Europe however this species is threatened. Picture from the Sierra Tejeda.

Hipparchia fidia
An endemic of the western Mediterranean. Picture from the Sierra Tejeda.

Hipparchia hermione
In previous posts I was able to show pictures of close relevants of this taxon Hipparchia (hermione) genava and Hipparchia fagi. In the Iberian peninsula Hipparchia fagi is limited to the Pyrenees. In the rest of the area the only species present is Hipparchia hermione. Picture is from Sierra de Albarracin.

Melanargia russiae
A species with a sporadic distribution over southern Europe.

Pseudochazara (hippolyte) williamsi
The nominate is a species from central Asia distributed from the south of the Ural to Mongolia. The taxon williamsi is restricted to some mountain regions in Andalucia. It is sometimes considered as a species on its own. Pictures are from the east of the Sierra Nevada between 2200-2400m

In next post some Hesperids from Spain.