What is eating the nasturtium flowers this week?
I noticed some holes were developing in the flower petals on Saturday.
A few of the flowers were covered with leaf or flea beetles. They are small, shiny black beetles with enlarged back legs.
The beetles seemed to have arrived from nowhere. When I went to check them again today, they were all gone. I wasn’t too concerned anyway because the nasturtiums had already produced a lot of seeds and they are getting to the end of their season. In a few weeks the heat will cause the plants to collapse and I’ll pull them out.
These might be the same kind of beetles that are commonly found feeding on Mexican evening primroses here. I know there are some flowering in the neighborhood.
I’ll have to check them.
It is not surprising that no one recognized our mystery seeds from last week, because they came from a plant that isn’t known for its seeds: the pineapple, Ananas comosus.
I was more than a bit surprised when I cut into a pineapple from the grocery store and there were seeds!
With a little research, it turns out that according to this article at Purdue, pineapples can produce seeds. They are used in breeding of new varieties and generally result from hand pollination. The seeds are apparently hard to germinate, which is why the commercial plants are usually propagated vegetatively.
Probably you have seen instructions for starting new pineapple plants from the tops of pineapple fruit. Our family cut off the fruit part and suspended the top in water (as shown here).
Pineapples are a type of bromeliad that grows naturally in tropical conditions. They don’t really enjoy our dry climate in Arizona.
Still, maybe someday it will flower and produce fruit.
If you are curious what the flowers look like and how pineapples are grown, the video from Dole pineapple shows more.
Have you ever found seeds in a pineapple? Have you ever grown one from a top?
We haven’t had a spider lately for Bug of the Week.
How about a crab spider waiting for a meal?
Crab spiders are known for using camouflage. In fact, adult female crab spiders have been shown to be able to change color to match the color of the flower they are sitting on.
So, why isn’t this crab spider purple, or sitting on a white or yellow flower? Isn’t being white going to wreck its chances of catching prey?
As this article from Wired points out, color matching does not necessarily help the spider to catch prey. One reason may be because bees can see ultraviolet light. Some spiders may reflect ultraviolet light, so even though the crab spiders look like they are matching the flower to our eyes, to the bees they stand out against their background.
This video suggests that standing out against the background may attract prey rather than dissuade it (it also shows crab spiders hunting).
Why would bees be attracted? The video does not explain this, but flowers have patches of ultraviolet that serve as beacons to the nectar. These patches are contrasting, and are thought to act like “signposts” directing the bees to the good stuff. Crab spiders may be trying to change the signs to direct flies and bees to themselves instead.
Now we are back to the question, why do female crab spiders change colors to match the flowers as we see them? Do you have any ideas?