i’m beginning to wonder what else is going to show up in my room…
this zebra spider was quickly moving over the inside (!) of my insect screen.

male zebra spider (salticus scenicus)

after caroline’s comment on the naming of alfred, i decided to call this one junior.
reading up on zebra spiders, i found out that this is a male (it has strongly elongated chelicerae.¹)
this species is part of the salticidae family (jumping spiders), whose jumps are very precise and cover distances up to 20 times their own body size.
most (all?) salticid spiders have 8 eyes, 4 of which are sitting on the front of the head like huge headlights. the central pair of these is bigger and is equivalent to telezoom lenses: the retinas are movable so it is possible to focus on any object, and even change the visual angle without moving the body.

the zebra spider is very common on housefronts, in houses and on rocks or gardenfences. male spiders are usually only seen between may and july.

while i was taking pictures, junior sometimes suddenly disappeared from the viewfinder, and i found him sitting on the outer rim of the camera lense. cool strategy: if something big supposedly wants to eat you, jump right at its eye!

nature often keeps me busy concentrating to not just stare at something with an open mouth.
in a recent class, we looked at developmental stages of plant embryos, from the zygote to a fully grown embryo inside a mature seed.

the animation below shows a young embryo that is being formed inside the ovule (entire structure). it will grow from a single cell to a complete, viable plant embryo, and the surrounding space will be filled with nutrients and storage substances that will give the little germinating seed the best chances possible.

animation: globular embryo (arrow) in an ovule of capsella bursa-pastoris.
differencial interference contrast microscopy and herr-prepared specimen

there are lots more pictures available, i’ll hope to find the time to upload them.

meet alfred the book scorpion (also: house scorpion):

book scorpion (chelifer cancroides)

i noticed this little guy crawl up from behind a shelf in my room.
pseudoscorpions (they resemble scorpions, but lack the long abdomen and stinger of “real” scorpions) usually hunt for small insects like psocoptera (booklice, barklice), so i think he’ll be allowed to stay in my room.

i named him alfred, after batman’s butler.

over at somethingcrawlinginmyhair.com, there’s an article about book scorpions and the challenge of identification by tim eisele.

last week, i took part in a practical class dealing with specific kinds of microscopy – namely confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM).
while we’re still waiting for the results of the second part, we’ve had plenty of time to play around with the CLSM.

here’s one of the numerous animations:

it shows part of a leaf of arabidopsis thaliana, that was genetically modified in a way that makes certain structure molecules within the cell walls visible.

to be more specific, the sequences of the green fluorescent protein (GFP, originally a gene of the crystal jellyfish, aequorea victoria) and a corresponding microtubule binding domain were inserted into the plant’s DNA, so that the cell walls would emit green light when exposed to light of a particular frequency (not all cells actually produced these molecules).
autofluorescense of chloroplasts is displayed in red.

using the CLSM, about 20 images were recorded at different levels of the leaf. these layers were then rendered in an animation that highlights its tridimensionality.

the image width equals 150 μm, that’s approx. 1/7th of a millimeter.