Monday, 29 April 2013

Butterfly chemistry

Registration of an Orange Tip (Anthocharis cardamines/Oranjetipje) on its typical host plant Cuckoo Flower (Cardamine pratensis/Pinksterbloem).

For those who are interesting some information from Wikipedia: The ♀ lays eggs singly on the flowerheads of Cuckoo Flower, Garlic Mustard and other species of wild crucifers, all of which contain chemicals called glucosinolates. Selection of foodplants is triggered by the presence of mustard oils and their derivative glucosinolates, which (in Pierinae) are detected by chemosensory hairs on the fore-legs. Reproductive rate of ♀♀ appears to be limited by difficulties in finding suitable hosts. As a consequence, the species has evolved to use a wide range of crucifers.
The eggs are white to begin with but change to a bright orange after a few days before darkening off just before hatching. Because the larvae feed almost exclusively on the flowers and developing seedpods there is rarely enough food to support more than one larva per plant. If two larvae meet one will often be eaten by the other to eliminate its competitor. Newly hatched larvae will also eat unhatched eggs for the same reason. To stop eggs from being laid on plants already laid on the ♀ leaves a pheromone to deter future ♀♀ from laying. The green and white caterpillar is attacked by several natural enemies (notably Tachinid flies and Braconid wasps). Pupation occurs in early summer in scrubby vegetation near the foodplant, where they stay to emerge the following spring. Recent research suggests that the emergence of the butterfly may be delayed for as much as two years, thus insuring the species against unfavorable conditions in a given season.

* Canon EOS 5D Mark II, 100mm/f2.8; ISO-400, f6.3, 1/250s; -0.3 stop, hand held.

Sunday, 28 April 2013

Spring flowers III

Two lonely Blue Bells (Hyacinthoides non-scripta/Boshyacint) taken with backfocus :-). The beech forest has been transformed into a green oasis over the last week.

* Canon EOS 5D Mark II, 17-40mm/f4 @ 17mm; ISO-400, f16, 1/160s; +0.7 stop; hand held.

Saturday, 20 April 2013

Spring flowers II

Oxlip (Primula elatior/Slanke Sleutelbloem) is another spring jewel; showers yesterday evening and a cold night took care of a myriad of dew drops at sunrise.

* Canon EOS 5D Mark II, 100mm/f2.8; ISO-800, f4, 1/250s; hand held.

Sunday, 14 April 2013

Spring flowers I

Luckily there are Wood Anemones (Anemone nemorosa/Bosanemoon) close to my home! More than 25 years ago I drew them on my marriage card; today I made this photo around sunset after a beautiful spring day (the first with 20+°C degrees). The interaction of the quality of light (which is always different) and a polarization filter caused the bluish-orange color contrast (it is not a Photoshop trick!).

* Canon EOS 5D Mark II, 100mm/f2.8; ISO-800, f4.5, 1/80s; polarization filter; hand held.

Sunday, 7 April 2013

Tufted tranquility

♀ Tufted Duck (Aythya fuligula/Kuifeend) at sunrise after a cold night (it was below -5°C last night, a record for this date!) floating on a ‘steaming’ lake. Easeful and peaceful! They say that temperatures will rise rapidly the coming week. Spring will arrive soon now!

* Canon EOS 7D, 500mm/f4.0; ISO-400, f5.6, 1/100s; +0.7 stop; bean bag.

Tuesday, 2 April 2013

Frog perspective

Moor Frog (Rana arvalis/Heikikker) in a hard backlight and a soft pastel sun-from-behind setting. The last 2 photos show a ♂ Moor Frog is mounted to a ♀ Green Frog (Rana esculenta/Groene Kikker). The photos are taken in a sheltered pool on the Strabrechtsche Heide. I has been a difficult season for Moor Frogs this year. They appeared at March 18th in the south of our country, when we had a couple of warmer days. But soon after that king winter returned. Even now in April we still have serious strong north-easterlies with sub-zero nights. In early morning all water is covered with a thin sheet of ice. I don’t know what happened to the Moor Frogs during this prolonged cold and frosty period. But today in the afternoon sun they are out. There are also several jelly spawn lumps in the water containing eggs with frost damage. The ♂♂ are not blue as usual, but grayish. Is the display already over the top?

* Canon EOS 7D, 300mm/f4.0; ISO-200, f4.0, 1/1600s; bean bag.
* Canon EOS 7D, 100mm/f2.8; ISO-400, f7.1, 1/400s; hand held.
* Canon EOS 7D, 100mm/f2.8; ISO-400, f7.1, 1/500s; -0.3 stop; hand held.