Tuesday, 8 March 2016

Tenerife and La Gomera - Species accounts IV - Nymphalidae (partim) & Hesperiidae

Pararge xiphioides

Of the 3 Pararge species in Europe remarkably 2 are island endemics with Pararge xiphia being endemic to Madeira and P. xiphioides being endemic to the 5 westernmost Canary islands. In Madeira also Pararge aegeria - common all over Europe - is present but - again remarkably - although the first sightings of this species on Madeira were only in the 1970's - so presumably this species is introduced - genetically the Pararge aegeria from Madeira are near identical to N-African P. aegeria and not to European ones.
As P. xiphioides is the only Pararge on the Canary islands it is easily identified. Differences from P. aegeria can however easily be seen. The front wing has the outer margin straight to slightly rounded and the hindwing underside has a clear white mark at the costa.

Male, notice the shiny androconial patch on the front wing

male

female

female, apparently more contrasting than males on the underside with greyish dusting along the outer margin 

For the several Hipparchia taxa on the islands we were way to early, flight period for these species starts in may and lasts until late autumn.

Thymelicus christi

As the previous species this one is present on the 5 western Canary islands, it is the only skipper species present on the Canary islands. The Wiemers article is a bit confusing about the flight period,the phenology table in the article mentions that this species flies from February on but in the text the earliest date mentioned is the 11th of March. The statement that the flight period starts in February in the general field guides is probably taken from the Wiemers article. So I was not hoping to find adults. At a dry coastal barranco north of Vallehermoso, La Gomera, I checked 50+ Brachypodium bushes in search of larvae but couldn't find anything. Later on the same day we visited a valley just west of Vallehermoso, more inland. At the edge of a small agricultural area there was a small slope full of Brachypodium that surprisingly had several adult males of Thymelicus christi flying around!





Monday, 7 March 2016

Tenerife and La Gomera - Species accounts III - Nymphalidae (partim)

Vanessa vulcania

This is another endemic with a peculiar story. This species is only present on the Canaries and on Madeira and is a specialist of the local nettle species (mostly Urtica morifolia but also other Urtica species) that grow at the borders and open places of the laurel forest. The butterfly itself is a very good flyer and can be found all over the islands, even on the dry - eastern - Canary islands but for reproduction apparently largely depends on the laurasilva zone. The strange thing about this species is that its nearest relative is not our European red admiral Vanessa atalanta but the Indian red admiral Vanessa indica living in the eastern palearctic from NW-India to the east. Vanessa vulcania has long been considered a subspecies of Vanessa indica but nowadays mostly is considered a species on its own, for example on differences in the larval stages (see f.e. this article). The hypothesis is that during the Pliocene (some 2 to 5 million years ago) climate was more humid around what later became the Mediterranean area creating a habitat suitable for laurel forests so probably the common ancestor had one large distribution from the west of N-Africa to the eastern palearctic. The ice ages following this warmer period and the subsequent forming of N-African and W-Asian deserts made the distribution to split up and so it became possible for both taxa known today to evolve separately.




I found the species to be common and adults - as strong flyers - can be seen almost everywhere. Most specimens were damaged in some way so probably most winter as adult.

Vanessa virginiensis

This is a nearctic species mainly occuring in central America and migrating north into north America in spring and summer. In Europe it can be found in the west of the Iberian peninsula and on the Canary islands and Madeira. I couldn't find back when the first observation were done in the Canaries but apparently it was widespread in at least Tenerife until it seemed to have disappeared in the 1970's with no observations until the early 1990's. Hence the statement in some field guides the species was extinct in the Canary islands. However since halfway the nineties more observations have followed.
Unlike the statement in the Wiemers article on the butterflies of the Canaries the larval foodplants used are not nettles but herbaceous plants with in some kind rather velvety leaves like Gnaphalium luteo-album or Filago gallica (I checked some Filago-like plants on La Gomera but didn't find caterpillars). For this reason this species is most likely best to be found in open landscapes like abandoned fields or scarcely grown hillsides. Kinds of landscapes that some naturalists don't visit while being at the Canary islands as these or not the most typical Canarian landscapes. Maybe this is the reason the species sometimes seems to disappear for years... The adults however are strong flyers so can be seen at more urban locations as well. This is what happened to us. We were planning to visit Mt. Teide from the north side from our base at La Orotava. On the way however we saw road signs indicating the road to be closed due to snowfall the previous day. To check this with some local folks we parked along the way and in some small roadside park I saw a flowering hedge attracting lots of Nymphalids. The first one I got a decent look at was one of 2 American painted ladies! Later on we saw a third individual on La Gomera in the valley where we had the Gomera cleopatras.




Danaus plexippus

Another Nearctic migratory species. The Monarch is probably the best known migratory butterfly in the world. It is already known from the Canary islands since the 1880's. It is easy to find in some urban parks where the larval foodplants are used (Asclepias and Gomphocarpus species). Although I searched all possible larval foodplants in the botanical garden of La Orotava I could only find adults (at least 5). In la Gomera I saw singletons in Vallehermoso, Agulo and San Sebastian.

female

male (recognizable because of the black egg-like androchonial scales on the hindwing)


I've been on the lookout for its African relative Danaus chrysippus but unfortunately didn't observe that species. It seems to be more local on the western Canary islands than its big brother occurring mainly in rather dry coastal barrancos. A good region seems to be the barrancos to the east of Punta del Hidalgo but unfortunately when we visited that location Tenerife was still in the middle of the depression at the beginning of our stay.
Red Admiral Vanessa atalanta we saw regularly at different locations but in smaller numbers than Vanessa vulcania.
Another remarkable Nymphalid observation was the fact that when we returned from La Gomera suddenly we saw Vanessa cardui all over with the species in numbers at every sunny open location we stopped, some just sunning and behaving territorial, others just flying by in N to W direction.

Vanessa cardui



Sunday, 6 March 2016

Tenerife and La Gomera - Species accounts II - Lycaenidae

Zizeeria knysna
This is a species with mainly an African distribution reaching Europe at its southern limits. Its habitat in southern Spain and the Canaries are all kinds of anthropogenic grasslands from park lawns to fallow lands.
I only have some faint images due to the butterflies being very active every time I saw them. I saw the species on a construction zone like area near Las Galetas (TF) and in the park of San Sebastian de La Gomera (LG).



Cacyreus marshalli
This South African species has been accidentally introduced into southern Europe in the late 1980's with Pelargonium plants and has since then spread all over the Mediterranean area. It is present now almost all over the Canary islands mainly to be found in the direct neighborhood of human presence as the larvae live in Pelargonium flower buds. By pure accident I noticed a flower bud of a Pelargonium that was eaten out and found a caterpillar inside.





Cyclyrius webbianus
This is one of the most special endemics of the Canary islands. Its nearest relative is a species of Mauritius at the complete other side of Africa that since its discovery more than 100 years ago has only a few records. The hypothesis is that the common ancestor once lived all over Africa but got out competed by other more specialized species of blues. Also in the Canaries Cyclyrius webbianus is a generalist when it comes to larval foodplants but seems to have it difficult to compete with other species of blues.
I saw one individual near Masca, one near Punta Teno and some 10-15 individuals near the picnic area on the road from Chio to Teide. Apparently this species is very common in summer on the Teide but numbers drop in winter. At 1500+m between the patches of snow still several were active in February around bushes of a Lotus species. First time I watched butterflies in the snow!




From the other species of Lycaenids present on the islands I only saw Lycaena phlaeas (common but never in numbers) and Lampides boeticus (several, especially in lower areas).

Lampides boeticus


Friday, 4 March 2016

Tenerife and La Gomera - Species accounts I - Pieridae

Pieris cheiranthi - Canary Islands Large White
This species is closely related to the Large White Pieris brassicae, a species common all over Europe. Unlike the Large White its Canarian counterpart is more a habitat specialist. Its native foodplants (Crambe strigosaDescurainia millefolia) are plants mainly to be found in humid conditions in the north of the islands in gullies and barranco's from sea level up to the lower laurasilva zone. It was considered extinct on La Gomera with the last sightings half way the seventies but recently a few reports of the species in the N of the island have been made. I visited the exact location on La Gomera mentioned on pyrgus.de but unfortunately only found Pieris rapae adults and larvae on the widely present secondary foodplant Tropaeolum majus. In Tenerife the species is still relatively widespread in the north of the island, as well in the natural habitat as in secondary habitat in towns where the year round irrigated parks and gardens form a secondary habitat. However there are reports of numbers having decreased sincerely on Tenerife. On La Palma (ssp. benchoavensis) the species is still widespread with numbers appearing to be stable.

Pieris cheiranthi, female underside, Barranco de Ruiz

Pieris cheiranthi, female upperside, same individual

Pieris cheiranthi, male upperside, La Orotava botanical garden


Gonepteryx cleobule cleobule - 'Tenerife' Cleopatra
The Canary islands cleopatra Gonepteryx cleobule has 3 subspecies that according to some genetic studies should be considered as species. However the external characters between the subspecies seem to be individually variable and no differences seem to exist in larval stages or ecological preferences. As with previous species this taxon is present mostly in the north of Tenerife. Habitat are the less dry scrub zones from sea level up to the open zones in the laurel forest. Larval foodplants are different species of Rhamnus.
I saw up to 10 individuals in the Barranco de Ruiz. Unfortunately all of them where very active so the best picture I could get was this one of a fly by male. At least the rather rounded hindwing is visible. 

Gonepteryx cleobule cleobule, male, Barranco de Ruiz

Gonepteryx cleobule eversi - 'La Gomera' Cleopatra
This taxon is widespread in the northern half of La Gomera. I saw lots of them near Vallehermoso.

Gonepteryx cleobule eversi, female, Vallehermoso

Gonepteryx cleobule eversi, male, Vallehermoso


The Euchloe species on Fuerteventura and La Gomera fly from december to april, the one in Tenerife, Euchloe eversi, however flies at higher elevations and normally only starts to fly half march (Masca region) or end of march (CaƱadas environment on Mt. Teide) to june with some solitary butterflies sometimes flying earlier. I have been looking at the Masca location but unfortunately weather conditions were bad for butterflies that day with strong winds even forcing the painted ladies down. 

The African migrant Catopsilia florella is known from the most islands of the Canaries. I have been on the lookout for the larval foodplant. In the Canary islands the species uses a very conspicuous exotic (African) plant that is sometimes used in parks or gardens, Cassia didymobotrya. Every time I saw this plant (only a few times) I took some time to look for caterpillars but unfortunately wasn't successful. I suspect the plant is being used more in the southern tourist resorts, locations I tried to avoid largely... Information on ecology and life cycle of this species can be found on pyrgus.de.

More to follow...




Wednesday, 2 March 2016

Canary Islands - Tenerife and La Gomera - Introduction

As this spring I will have a lot of fieldwork at work and won't be able to do a real spring trip and my partner  had some days overtime of 2015 at her work she had to take before the end of February 2016 we decided to do a very early trip and visit 2 of the 7 Canary islands at the end of February. We left at the 18th arriving late afternoon in Tenerife and returned at the 28th.

Before heading to the observations made first some background information on the Canary islands in order to better understand what butterflies are present and why they are present at the Canary islands.
The Canary islands are part of what is called the Macaronesian (biogeographical) region, these are the volcanic islands in the Atlantic ocean and apart from the Canary islands comprise of the other archipelagos the Azores and Madeira. The fact that these islands arose through volcanic activity means they were never connected to the mainland of Europe or Africa, unlike other European islands like the British Isles or Corsica. Because of this the butterfly fauna is rather poor. The oldest Canary islands, the eastern Lanzarote and Fuerteventura, were formed some 20 million years ago and gradually through time the more western islands appeared with El Hierro the latest to form some 750.000 years ago. This long period of time however means that butterflies that could reach the islands in an early state would get isolated from populations of the mainland and could evolve in different ways than their relatives on the mainland from their common ancestor. And this is exactly what happened meaning that from the 40 butterfly taxa that have ever been seen on the Canary islands 16 taxa are endemic to one or more of the Canary islands or to bigger parts of Macaronesia.

Species
Endemism
LA
FU
GC
TE
LG
LP
EH
Remarks
Pieris cheiranthi
Can



x
(x)
x

(1)
Pieris brassicae

m






(2)
Pieris rapae

x
x
x
x
x
x
x

Pontia daplidice

x
x
x
x
x
x
x

Euchloe hesperidum
Can

x





(3)
Euchloe grancanariensis
Can


x




(3)
Euchloe eversi
Can



x



(3)
Euchloe charlonia

x
x






Colias croceus

x
x
x
x
x
x
x

Catopsilia florella

x
x
x
x
x
x


Gonepteryx cleobule cleobule
Can



x



(4)
Gonepteryx cleobule eversi
Can




x



Gonepteryx cleobule palmae
Can





x


Danaus plexippus


x
x
x
x
x
x

Danaus chrysippus


x
x
x
x
x


Hypolimnas misippus




x
x
x


Vanessa atalanta

x
x
x
x
x
x
x

Vanessa vulcania
Mac

m
x
x
x
x
x

Vanessa virginiensis



x
x
x
x


Vanessa cardui

x
x
x
x
x
x
x

Argynnis pandora




x
x
x
x

Issoria lathonia



x
x
x
x


Hipparchia tamadabae
Can


x





Hipparchia wyssii
Can



x




Hipparchia gomera
Can




x



Hipparchia tilosi
Can





x


Hipparchia bacchus
Can






x

Maniola jurtina



x
x
x
x
x

Pararge xiphioides
Can


x
x
x
x


Callophrys rubi




(x)



(5)
Lycaena phlaeas

x

x
x
x
x
x

Lampides boeticus


x
x
x
x
x
x

Leptotes pirithous

x
x
x
x
x
x


Azanus ubaldus


x
x





Cacyreus marshalli

x
x
x
x
x
x


Cyclyrius webbianus
Can


x
x
x
x
x

Zizeeria knysna

x
x
x
x
x
x
x

Aricia cramera



x
x
x
x
x

Polyommatus icarus celina

x
x





(6)(7)
Thymelicus christi
Can


x
x
x
x
x

Species in green are species I could observe during our stay

Remarks:
(1) There are unconfirmed sightings of Gran Canaria, possibly this concerns accidental import with the secondary larval foodplant Tropaeolum majus. The species was considered extinct on La Gomera as there were no confirmed sightings since the mid seventies but recently a small population was found on the very northern tip of the island (see http://pyrgus.de/Pieris_cheiranthi_en.html). It is unclear to me if this is a long overlooked population or maybe this also concerns accidental (re)import. There are some other unconfirmed sightings from the N of the island.
(2) migrant or accidental import via agricultural activities
(3) recent genetic research splits up the 3 green-striped whites as distinct species, this is already recognised as such by Fauna Europaea (FE)
(4) According to some studies also the Canary cleopatras constitute different species, according to other they don't even deserve the status of subspecies. I chose the middle road in following FE and considering them here as one species but give credit to the subspecies.
(5) Only known from the late 19th century, voucher specimens are present from one collector only. Maybe the status of this species should be re-evaluated. It wouldn't be the first case of intentional or unintentional mistakes in museum specimens.
(6) Recent studies show P. icarus consists of 2 species with P. celina being a southern counterpart of the European P. icarus. I follow FE here but mention celina as to make clear what population is present on the islands
(7) There are several unconfirmed sightings of P. icarus (celina) on other islands but to my knowledge no populations exist on the western islands

The 2 eastern islands are the oldest without any real mountains (mostly below 800m) and are close to the African coast making those the driest islands with lots of steppe to dessert like habitat. The 4 westernmost islands (from E to W: Tenerife, La Gomera, La Palma and El Hierro) are more mountainous with the Teide mountain on Tenerife reaching up to 3700m, constituting the highest mountain of Spain, higher than the Pyrenees or Sierra Nevada.

Mount Teide as viewed from the La Gomera - Tenerife ferry

Because of their western position this mountainous areas catch up a lot of humid from the northern trade winds in that part of the ocean. This creates a habitat unique in Europe of humid laurel forests on the north side of these islands from more or less 800m to 1500m. More about this in the species accounts.


Laurel forest at El Cedro - La Gomera

This also means that the southern sides of the islands are considerably drier than the northern sides (in Tenerife the driest locations get less than 100mm rain per year, the wettest locations get more than 1000mm rain per year), creating a high diversity in habitats on a small area.
In between these eastern and western islands is Gran Canaria, an island where also habitats form a transition between eastern and western islands. There used to be some laurel forest on Gran Canaria too but due to human activities most of it (>95%) disappeared.

The butterflies can be roughly divided in a few groups:
1) First of all, there is a group of endemic butterflies, as mentioned earlier.
2) Another group are butterflies with a wide distribution in (SW-)Europe and N-Africa, for example Lycaena phlaeas and Maniola jurtina
3) A third group are butterflies that are highly migratory, this group has butterflies of African origin like Lampides boeticus and Catopsia florella as well as a few butterflies of Nearctic origin like Danaus plexippus.

For everyone wanting to visit the Canary islands for butterfly watching I recommend reading the 1995 paper by Martin Wiemers, a little out-dated (for example Leptotes pirithous is only since recent times part of the Canarian butterfly fauna) but still very informative.

Species accounts of the most important species I saw during my February trip will follow in a next part.

Vanessa vulcania flying off...