One hot summer day I was walking in Cedar Bluffs State Preserve, in Mahaska County Iowa. I had my camera set up for closeup work. I was actually hunting snails. As I walked along the creek bottom area, I noticed something funny with the jewelweed flowers there.
Jewelweed has sort of a funnel shaped flower, with a long tube at the end. That tube holds nectar. The tubes on several of the flowers were missing their ends.
I figured a nectar thief was somewhere close. I looked around for one, and sure enough, I caught one at work. This harvestman (a.k.a. daddy long legs) was walking on top of the jewelweed flower, and then dipped down and hung upside down at the end of the tube. I only got one shot--I was at the end of the roll, and he was gone by the time I had changed rolls. I am sure he was the nectar thief, although I wish I had a better picture.
What is a nectar thief? Well, flowers sort of make a choice. They can give a lot of nectar out, and invite all kinds of insects to imbibe in exchange for transferring the pollen. Simple flowers like apple flowers or rose flowers (the wild type, not the domesticated type) do this. The problem is that this method is pretty inefficient. A lot of types of insects visit the flowers, but usually few are of the right size or structure to pollinate the flower. Other flowers "choose" to hide the reward. The insect that is able to collect the nectar must be of a certain size, or have a long tongue, for example. Sometimes a degree of strength is needed. For example, a petal is formed in such a way that a strong insect like a bumble bee needs to push a petal away and force itself down into the flower. These can be called exclusive flowers. Examples would be jewel weed, dutchman's breeches, and squirrel corn. Usually in exclusive flowers, the reward given to the pollinator in an exclusive flower is greater than it would get in a non-exclusive flower. The bee needs to have an incentive for going to the extra work to collect nectar from one of these flowers. This is a successful strategy for exclusive flowers--pollination is more efficient, because the total amount of nectar needed is lower than for non-exclusive flowers. However, it is not a perfect world. There are insects, typically wasps and bees, that cheat the system--they can get nectar out without pollinating the flower. And, as you can see, the harvestman does it too! That is a nectar thief.
