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Showing posts with label pollination. Show all posts
Showing posts with label pollination. Show all posts

Thursday, February 14, 2019

Animal Attraction


People are more like animals than we like to admit sometimes. Rather, we tend to believe that animals can be so human sometimes. One area where the lines between humans and animals can become blurred is that of courtship rituals and relationships. This Valentine’s Day let’s look at “love” in the animal world. Hopefully our finned, feathered, and furred friends don’t feel as awkward as we do.
Many times, in the animal world it is the female who chooses a mate. Males might compete with each other not by fighting, but other means. Bowerbirds build little houses with decorated yards to impress females. Prairie chickens and sage grouse gather in a lek, where the males display for the females. South American birds called manakins show like an 80s break dance fight from a movie. It reminds me of teenage boys trying to upstage each other to get a girl’s attention.
In other species, brute strength carries the day for males eager to win mating rights. Large mammals like elk and bison have a dominant male who controls a harem of females, unless a younger and stronger challenger is able to put him out to pasture. This behavior reminds me of countless schoolyard and lunchroom fights over a girl.
Once these critters become an item, how long does their relationship last? It depends on the critter, just like with us. Some species are monogamous pairs, some are promiscuous males, and some are promiscuous females. For those that have a hard time getting around, like corals and clams, it’s free love. Look around at our own society and you’ll see the same scenarios, though not always for the same reasons.
In promiscuous relationships it is the female who raises the young with no paternal help in most cases. The bison and elk, where a male controls a harem, are male promiscuous. He will mate with as many of the females as he can. His goal is to have as many offspring as possible, while the female’s goal is ensure that her offspring have the best chance of survival. Surely the strongest and most fit of the males has the genes that offer better odds.
Sometimes it is the female who gets around. Several species of primates and birds practice this. The female hopes for better reproductive success by keeping her options open. It may also have the advantage that comes with several males all believing the offspring are theirs. Since the male’s goal is to have as many offspring as possible, the uncertainty will make sure they are looking out for any that are potentially theirs.
Everyone’s favorite relationship is monogamy. A pair mates for life and we think it’s so sweet. It’s almost like they’re married. This behavior is seen in bald eagles and gray wolves, for example. In this situation, both parents care for the young. In most cases, the pair nest together year-round. Not so for the Laysan albatross like Wisdom, who we met a few weeks ago. While she has a monogamous partner, they spend most of the year apart, coming together only for the breeding season. Once they chicks fledge the nest, they all go their separate ways. Wisdom and her mate will see each other again next year.
The messiest mating strategy is dispersal. Wind pollenating plants (think of pine trees) use this method, as do many sea creatures. Some environmental cue triggers corals, clams, and other sessile critters to release sperm and egg cells simultaneously. The sea becomes a soupy mess as the currents mix everything together. The pinnacle of group sex, critters who have never met or even seen each other become proud parents of children drifting off to parts unknown.
Every species is adapted to whatever mating and parenting style works best to ensure the next generation will survive. A general rule of thumb: fewer offspring get more intense parenting, while more offspring get little to no parental care. Either way, parents are playing the percentages to make sure they win the mating game.
 This week's information comes from Nature Education and the Washington Post.


Thursday, July 27, 2017

Bats and White Nose Syndrome

Bats are a misunderstood and unreasonably feared critter. Some species rid our skies of pest insects, while others pollinate crops and other plants. Bat poop (guano) is a rich fertilizer. Attitudes are changing as people begin to appreciate the ecosystem services bats provide but now they face another threat, White Nose Syndrome.
White Nose Syndrome (WNS) is a fungal infection that is destroying bat colonies at an unprecedented rate. The fungus Pseudogymnoscus destructans was likely introduced from Europe inadvertently. It thrives in the cold strikes bats when they are hibernating. Bats hibernate to conserve energy when their food source (insects or fruit) is unavailable, but the infection causes them to wake from hibernation. Being awake increases metabolism and other bodily functions, and the bats starve to death because of burning through whatever energy they had stored to make it through the winter. To answer your next question, “How does being awake kill a bat?”, most of the calories you need in a day are just to keep you alive- breathing, circulation, and the biggest energy consumer- temperature regulation.
WNS spreads from direct contact with an infected bat or from surface contamination inside a bat cave. People can transport the fungus from cave to cave, so spelunkers must decontaminate clothing, shoes, and equipment in between caves. 
Bats infected with WNS (National Park Service photo)


WNS has killed millions of bats in the eastern parts of the US and Canada is spreading west. Last year the first case was discovered here in Washington. Washington Department of Fish and Wildlife conducted a bat count a few weeks ago at Northwest Trek as the beginning of an effort to monitor bat colonies and WNS. A follow-up count took place this past weekend and I took part.
The goal is to count the number of bats seen leaving and entering the nest. Exits minus entries is the total number of bats seen. The tricky part is seeing them as it gets darker. I did OK with this until about 9:20. The freaky part is not seeing the bats until they are inches from your face, then they turn away at the last second, mostly to my left. I could their wings flapping as they passed by my head.
By establishing a baseline this year the state hopes to track population trends that could indicate colonies in trouble. This can be tricky, though. Bats sometimes tend to not roost in the same location night after night. For example, the site I counted was unmonitored in the previous count. The only reason I was posted there was because on the way into Northwest Trek we heard the bats making sounds inside the park entryway. My total for the night was around 60 bats. Other sites inside the park had a lower count than during the previous survey. It is possible that my site had an increase since the last survey, but that is unknown since no one counted there the first time. 
Me counting bats
In just six years since its introduction, WNS had killed millions of bats with a mortality rate up to 100% in some colonies, according to the US Fish and Wildlife Service. Fighting back will be a long process, but the key first step is monitoring. I am glad I had a chance to take part in the beginning of what I hope will be a successful fight. WNS info this week comes from the National Park Service, one of many partners in the search for a cure.
NPS: https://www.nps.gov/articles/what-is-white-nose-syndrome.htm

USFWS: http://www.batcon.org/pdfs/USFWS_WNS_Mortality_2012_NR_FINAL.pdf