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Dispelling the Daddy Long Legs Myth

“Daddy Long Legs are one of the most poisonous spiders, but their fangs are too short to bite humans. But if they could, they would be deadly.”

daddylonglegsHave you heard this common myth?  This creature has long held on to this untrue legacy. While the Daddy Long Legs or Harvestman is in the Order of arachnids, having eight legs, so do scorpions, mites and ticks. True spiders have two segments or body parts; the cephalothorax (Greek for head-body) and the abdomen or gut. The abdomen of true spiders also has spinnerets for producing silk for web making.  Daddy Long Legs (of the Order Opiliones) have a fused cephalothorax and abdomen, or a single body part, and do not possess spinnerets. They do not produce silk and webs.  If you see one in a web it has probably fallen victim to a true spider.  Other differences are that Opiliones have no venom glands in their chelicerae (mouth parts), where true spiders have both fangs and venom.

Daddy Long Legs or Harvestman are opportunistic, and may eat other small insects but their primary diet is that of a decomposer, eating dead plants and fungi and sometimes dead animal material. That is why you will find them under dead logs and in other dead forest and garden debris. Since they lack venom glands, fangs or any other mechanism for chemically subduing their food, they do not have poison and, by the powers of logic, cannot be poisonous from venom.

How do Daddy Long Legs defend themselves from their predators? There are two ways besides outrunning them. First, in their limited arsenal of self-defense is the art of distraction.  If a leg is lost (some species may have the ability to throw off their legs) the separated leg will twitch for a few minutes. Some species’ legs have been recorded to twitch for up to an hour. The twitching is an adaptation designed to hold the attention of the predator while the Daddy Long Legs escapes to safety. A final defense found in some types of Daddy Long Legs is their ability to secrete a substance with a strong odor from their abdomen to discourage the predator. This secretion may be poisonous if eaten.  I could not find any studies on how many or much of this substance a mammal would have to consume to be affected.

In summary, you are safe to capture and observe Daddy Long Legs to your heart’s content and should not suffer any negative consequences, as long as you do not eat them!  –By Robin Lee, Education Programming Coordinator

What Makes Objects Float?

This week, the Junior Rangers teach team helped out with Nature Day Camp by teaching a lesson about water. H2O was this week’s theme and our team had prepared a lesson about buoyancy, surface tension and cohesion – aka what makes certain objects float. Buoyancy is defined as the upward force exerted by a liquid that opposes the weight of an immersed object. Each member of our team was responsible for teaching a section of the material. Junior Ranger Luke Knollinger introduced the topic by showing campers how to calculate the density of an object. If an object is denser than the water, it will sink. We also talked about animals that use surface tension to float, like the Water Striders (Gerridae). This group of true bugs distributes its weight to make it less dense and allow it to glide on the surface of the water.
During the lesson, the campers treated us to a rousing chorus of The Water Cycle Song – a song about how water is recycled through evaporation, condensation and precipitation. It was great! After we explained why things float, we needed to test out this new knowledge. The campers broke up into teams and constructed their own boats, using what they had learned to make them buoyant and fast. Once the boats were built, campers were able to race them against the other teams. Even though the power went out shortly after we left the building, we all still had a blast. ~Jr. Rangers Teach Team

So, Why is the Egg Blue?

By Jake Francis, Director of Environmental Education — There have been a number of bird species nesting in and around the Schrader Center for the last month (including red-shouldered hawks, red-bellied woodpeckers, mallards, and many more).  Recently we found hatched robin’s eggs on the ground along the Hardwood Ridge trail.

There are two interesting things going on in this photo. First, we see that the egg is bright blue (in fact this could be any thrush egg, but we know it is a robin because of the robin’s nest situated above the shell). The blue coloration of the egg is created by the deposition of the mother’s blood pigments on the egg, notice that the outer portion of the egg is blue while the inner side of the shell is not. There have been many scientists who have hypothesized about the adaptive significance of the blue coloration in thrush eggs. Some claimed that color blind mammals would be less likely to see a blue egg in a brown nest than a white egg, others believed that the blue coloration helped protect embryos from sunlight damage. Recent research suggests that perhaps the blue coloration of thrush eggs serves as a signal of their mothers’ fitness to male thrushes, causing them to invest more energy in feeding the young after they hatch. Some data supports that egg coloration correlates with the mother’s fitness in other families (e.g., Pied Flycatcher).  And, male Robins seem to feed supposed hatchlings from brighter eggs.

In this photo we can also see that an invertebrate was likely eating the remainder of the amniote of this egg (notice the trail of slug or snail excretion at the opening of the egg). This is the first instance that either I or Greg Park, Senior Naturalist, have heard of gastropods eating the left-over amniote of bird eggs. Perhaps some of our readers can lay out egg shells and try to catch a snail or slug red-handed!