PART 1 - IDENTIFYING BUTTERFLY AND MOTH SPECIES FROM THEIR PUPAE
When I started this website the intention was to provide a set of
dorsal and lateral photographs of the final larval instars of all Northern European macro Lepidoptera species. The
initial aim was to improve the pictures available to help identify larvae - how it has grown since that point in time!
It soon became clear to me that if I was going to spend time rearing Lepidoptera that it was well
worth photographing all stages through from the egg to pupa and also the adult. The change in appearance of a single
caterpillar over its lifetime is often as great as the difference between species so I started to photograph each
instar where there was a significant change in appearance. It followed that if the aim was to identify larvae in any instar that recording the approximate
size of the larva in each photograph was much more useful than recording the instar number - it is also a nightmare
trying to keep accurate records of which instar each larva is in when rearing ten or more species at a time!
I also started by photographing only one side of pupae, that which illustrates the difference between
male and female of each species. However since purchasing copies of the handbooks titled "Lepidoptera Pupae
(Central European Species)" by Jan Patocka and Marek Turcani I have realised that close up views of particular
areas of the pupae are also worth photographing to aid species identification. These are particularly useful when,
as often happens, one finds a final instar caterpillar and cannot be certain which species it is out of several
possibilities. Whilst one can always wait and hope that the adult butterfly or moth hatches in due course to confirm
identification, it is usually better (sometimes essential) to confirm identification so that one knows whether the adult
is going to emerge in the near future or if the pupa should be stored in a cool place outside to hibernate.
When comparing pupae with drawings or photographs it should be noted that the colour of pupae often changes
with time, thus many are light brown when they are first formed but gradually darken with time. In addition there are often
significant differences between pupae of the same species. The particular conditions and space in which a caterpillar pupates
and any disturbance in the pupation process can lead to distortions in the antennae, legs and wing cases. The hooks and other
fibres around the cremaster and other parts of the pupae are often bent or twisted in the process of pupation.
It follows that there will often be differences in shape between the photographs on the website,
the drawings in the "Lepidoptera Pupae" handbook and any other pupa of the same species.
NEW PUPA PHOTOGRAPHS - For those who have obtained a copy
of Lepidoptera Pupae - Central European Species, the new pages contain examples of sections of pupae labelled
with the corresponding Plate reference and Figure numbers in the Plate Volume handbook. Indexes can be
found at:- English Common names
(not yet available) _
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PART 2 - CHARACTERISTICS OF PUPAE REQUIRED TO HELP WITH THEIR IDENTIFICATION
The pictures below illustrate some of the key areas that are used to help with the identification
of pupae to a particular species. Wherever possible I will also include a photograph of the head part on the ventral side
including the forewing cases, antennae, legs etc.
The pupa shown on the right-hand side below was a bit twisted when the photograph was taken so the top of the pupa is a bit between the lateral and dorsal views.
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PART 3 - PROBLEMS PHOTOGRAPHING PUPAE
Anyone who has tried photographing pupae will know how difficult it
is to get good detailed pictures of the 'shiny' ones. I have tried a variety of ideas and find the following method of diffusing
light around the pupa reduces the reflections and usually gives excellent results.
For smaller pupae, less than 2cm long I have cut a 3cm hole in the top of a white
semi-transparent plastic box (such as those used for storing food etc.).
This box is about 11cm x 11cm by 4cm high and has the 3cm hole cut in the top of the box as shown in the picture below.
For larger pupae such as Hawkmoths, I use a taller box which also has a base about 11cm x 11cm but is about 9cm high and has a larger (6cm)
hole cut out of the lid.
These box sizes work well with most macro cameras such as the Coolpix range and DSLR cameras with a good macro lens. However getting
detailed photos requires a reasonable depth of focus and manual focusing gives the best results. Accurate manual focusing is easiest to achieve with a DSLR
camera which I have found yields results which are excellent for recording and identification purposes. When using this method I set the box up close to a window
fitted with a net curtain (to further diffuse the light) and place the pupae with
the 'sharp' end - the cremaster - nearest to the window.
After trying out a variety of backgrounds to rest the pupa on whilst taking the photographs, my preference is to use a leaf without too many veins and colour
variations. Where available I have found the back of a fresh Ivy (Hedera helix) leaf provides an excellent background. I mount the leaf on top of a small piece of blue-tack on a flat
card or other hard object, the area of leaf over the blue-tack can then be gently pressed down to provide a shallow groove to hold the pupa in position. After setting up the pupa on the leaf in the middle of the box and focusing
on it I usually find it necessary to reflect additional light onto the side of the box furthest from the window when taking the shot - this helps
to even out the lighting. In almost all cases you can get a good picture of the pupa without too much shine hiding the important characteristics - one of the most difficult
is the Lobster Moth (Stauropus fagi) pupa - see the photos on this website! Exposure times are often many seconds so mounting the camera on a tripod or Copy Stand is essential. Fortunately
most (but not all!) pupae will stay still once set up in the position required.
Sometimes, particularly when the pupa are newly formed, they will wriggle for hours which requires a good deal of patience to get a range of shots!
For recording pupal characteristics to aid identification it is essential to take photographs from three angles i.e. with the pupa on its back with
the proboscis pointing upwards (the ventral side), on the opposite (dorsal) side and on its lateral side so that the mesanotum etc. is clearly visible. It is particularly important
to get clear 'in focus'
shots of the area around the cremaster and may be necessary to take a couple of photographs of each side depending on your camera's depth of focus and the size of the pupa
Finally to get really good photographs it is essential to give the pupa a good 'clean-up' before you start.
This may sound easy but many pupae have stands of silk around the cremaster and it takes a magnifying glass, a small paintbrush, a fine pair of tweezers and a lot of patience
to remove the silk without damaging any important bits.
After that the pupa will almost certainly need a good wash down with the paintbrush to remove all the other particles - and even then all the bits that you have missed will be highly visible on the first photographs you take!
© Reg Fry 2009
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