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The Wayne's Word Bat, COVID-19 & Plant Page
Latest Update W.P. Armstrong, 1 May 2021
Bats Are Not To Blame For COVID-19, Humans Are: We Need To Live In Harmony With These
Remarkable Mammals; Not Remove Them From Their Natural Habitats & Sell Them In Markets
As I write the preface to this latest Wayne's Word page, the death toll from the disease COVID-19 caused by the virus SARS-CoVid-2 now exceeds 600,000 Americans. Coronaviruses (CoV) are a family of RNA viruses (Coronaviridae) affecting humans and other animals. Coronviruses causing respiratory illnesses in humans include the common cold, Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS) and COVID-19. [Note: Influenza (flu) is caused by a different RNA virus family (Orthomyxoviridae) that is spread to humans via domestic animals, such as chickens & pigs, living in close contact with people.] When human populations expand into unexplored tropical regions, we will undoubtedly be exposed to (or will spread) new and potentially dangerous viruses. This happened when Europeans arrived in North America, carrying germs which thrived in dense, semi-urban populations. Native Americans had never experienced smallpox, measles or flu before, and the viruses spread throughout the continent, killing an estimated 90% of indigenous people. Just because bats are apparently highly resistant to viruses does not make them a likely source of viruses dangerous to humans. We are not likely to ever catch any disease from bats, from which we are biologically remote. I am certainly not an authority on bats and I do not want to perpepuate misinformation about them. On the contrary, I want to point out how valuable they are to ecosystems throughout our planet. In fact, many species of these remarkakable flying mammals are now rare and endangered, and we need to live in harmony with them. W.P. Armstrong 9 Jan. 2021

   Please Click On Following URL: Bat Conservation International: Bats & COVID-19  
Outbreaks of emerging diseases have been linked to human destruction of nature. When tropical rainforests are cleared for grazing cattle, soybeans, oil palms, etc., or to build roads and settlements, wild animals are forced ever closer to humans and livestock, giving viruses an opportunity to escape from their original hosts.

The precise origin of the coronavirus COVID-19 (SARS-CoV-2) that has killed millions of people throughout the world has not been established as of June 2021. It is discussed in a recent article by Nicholas Wade "The Origin of COVID: Did People or Nature Open Pandora's Box at Wuhan?" in Bulletin of the Atomic Scientists (5 May 2021). Some scientists believe that it crossed into humans from an animal species; escape from a virus research lab in Wuhan, China is another hypothesis. Laboratory research has involved genetic manipulation of viruses to predict how they could infect humans. This research is called "gain of function," a term used to describe any field of medical research which alters an organism or disease in a way that increases pathogenesis, transmissibility, or host range (the types of hosts that a microorganism can infect). This research is intended to reveal targets to better predict emerging infectious diseases and to develop vaccines and therapeutics.

Furin Cleavage Site In SARS-CoV-2

Furin is a vital enzyme in humans coded by the furin gene. Some proteins are inactive when they are first synthesized, they must have sections removed in order to become active. Furin cleaves these sections and activates the proteins. Furin occurs in the spike glycoprotein of the COVID-19 virus. This is an oversimplified explanation of a very complicated molecular subject beyond the scope of Wayne's Word. The origin of SARS-CoV-2 furin cleavage site is a fascinating research topic for molecular biologists.

Since there are only 20 kinds of amino acids, there are more than enough codons to go around, allowing some amino acids to be specified by more than one codon. The amino acid arginine, for instance, can be designated by any of the six Messenger RNA codons CGU, CGC, CGA, CGG, AGA or AGG, where A, U, G and C stand for the four different RNA bases. Different organisms have different codon preferences. Human cells designate arginine with the codons CGT, CGC or CGG. According to Nicholas Wade's references, CGG is the least popular codon for arginine in coronaviruses.

  Origin of COVID: Did People or Nature Open Pandora's Box at Wuhan?  
The Wayne's Word Table of DNA Base Triplets, Codons & Anticodons

Additional COVID-19 Pages & Bat Pollinated Plant Images At Following Tabs
  Sea Beans  
  Sausage Tree  
With 1400 species and many more undescribed, bats are a very successful mammal. They are also one of the most misunderstood animals on our planet. In one square mile of the Amazon rainforest there may be up to 100 different species. Their ability to fly across natural barriers undoubtedly accounts for their genetic isolation and abundant speciation. They are distributed throughout the Earth except for extreme deserts and polar regions. During the hours of darkness (nocturnal) they fill the ecological niches of birds, feeding on insects, fruits and fish. Although they receive a lot of publicity from sci fi movies, only 3 species are classified as "vampires." Bats can fly as fast as many birds and are more maneuverable due to their remarkable echolocation. Their biological "sonar" is like a series of clicking sounds in which they detect objects while flying in pitch darkness. They can even detect insects and it has been estimated that some insectivorous bats may consume 500-1,000 mosquitos in one hour!

Bats belong to the mammalian order Chiroptera within the clade Laurasiatheria, a large group of placental mammals that includes hedgehogs, even-toed ungulates, whales, bats, odd-toed ungulates, pangolins, and carnivorans, among others. Its last common ancestor is supposed to have diversified about 76 to 91 million years ago. The Laurasiatheria clade is based on DNA sequence analyses and retrotransposon presence/absence data. The name comes from the theory that these mammals evolved on the supercontinent of Laurasia, after it split from Gondwanaland when Pangaea broke up. Of course, scientific theories can be updated when more data is available. Bats are not closely related to rodents; instead, they formed their own group (clade) early on that may share a common ancestor with mammals that eventually evolved into horses, pangolins, whales, and dogs.

In 1915 Alfred Wegener, a German climatologist and geophysicist, published an expanded version of his 1912 book The Origin of Continents and Oceans. This novel hypothesis, which has now been confirmed by other scientists, states that continents are not fixed; instead, their relative positions and the positions of the oceans have changed over time. Wegener's hypothesis led to the science of plate tectonics, where scientists study the gradual movement of large plates of the earth's crust along major fault zones. About 200 million years ago, the continents were joined into one supercontinent that Wegener called Pangea (Figure A). By 135 million years ago, Pangea had divided into two large subcontinents called Gondwanaland and Laurasia (Figure B). In the great southern subcontinent Gondwanaland, South America and Africa were connected with each other and with Antarctica, India, and Australia. This is roughly the time when the first flowering plants began to appear on earth. By 65 million years ago, about the time when dinosaurs became extinct, the continents had divided into positions resembling the present-day configuration (Figure C). As of April 2000, the continents resembled the configuration shown in Figure D.
Our well developed cell-mediated and antibody-mediated immune responses can overreact to SARS-CoVid-2 virus, the cause of COVID-19 disease. In fact, severe COVID-19 cases in some people may involve a "cytokine storm" or cytokine release syndrome (CRS), a massive immune response in the lungs that can be fatal. It is like the immune system is overreacting and causing inflammation and collateral damage to lung tissue. Bats can apparently carry related viruses with impunity. One hypothesis to explain why these viruses are so severe in humans involves their tolerance to higher temperatures. Ordinary viruses are sensitive to higher temperatures; hence, fevers up to 105 degrees Fahrenheit can kill them. The flight of bats generates body temperatures similar to our highest fevers. Perhaps the viruses have adapted to these higher body temperatures. Research on bats may help to explain how to survive and conquer pandemic viruses.

  Cytokines (Lymphokines) In Poison Oak Cell-Mediated Immune Respone  
On a positive note, bats are very important for the environment. They provide valuable insect pest control, fertilizer, seed dispersal and vital pollination for nocturnal blossoms. According to the United States Forest Service Rangeland Management Botany Program, more than 300 species of food-producing plants depend on bats for pollination, including guavas, wild bananas, cacao and mangos. The pollination of plants by bats is called chiropterophily. Although tropical figs are pollinated by symbiotic wasps, fig fruits (syconia) are an important food in the diet of bats. I once sat beneath a tropical fig and watched bats devour the sweet, fleshy fruits. Fig seeds are dispersed by defecating bats on the branches of rainforest trees. In fact, this is how epiphytic strangler figs get started, eventually taking over and shading out the host tree.

Speaking of seed dispersal, the world's largest mammal migration involves straw-colored fruit bats (Eidolon helvum) that are crucial to Africa's reforestation. Up to 10 million of these fruit bats descend on Zambia’s Kasanka National Park every year, dispersing millions of seeds as they go. Listed as near threatened on the International Union for Conservation of Nature’s red list, the straw-colored fruit bat is one of the largest fruit bats (flying foxes) in Africa. There are fears that if their numbers drop below a certain amount, the colony may not be able to maintain its stabile population size.

  Strangler Figs & Banyans Of Tropical Rainforest  

Pendant, flower stalk of a cultivated banana plant. Purple bracts at the end resemble a large bud. Some of the basal purple bracts have fallen away exposing clusters of female flowers. Farther up on the stalk are immature bananas that developed from female flowers. Bananas include many cultivated varieties (cultivars), including the fleshy, nutritious bananas that are peeled and eaten raw, and firm plantains that are fried and roasted like delicious sweet potatoes. Cultivated banana crops develop without pollination & fertilization; however, bats are vital for wild bananas!
Bats pollinate wild bananas and disperse their seeds. But the commercial bananas we eat are seedless and do not require pollination. See excellent articles in Bat Magazine (left) Volume 26 Issue 4 dedicated to this subject.

  Bat Conservation International: Bats and Disappearing Wild Bananas  
Bats pollinate wild bananas and disperse their seeds. But the commercial bananas we eat have been seedless and without the need of pollination for thousands of years. They are grown only from suckers cut off a mother plant and transplanted around the tropics. So who needs bats these days? Well, we do if we want to keep eating bananas. The plants that produce all that tasty fruit are so genetically similar that a single disease could devastate the global crop. In fact, some scientists warn that commercial bananas may already be at great risk from a recently reported fungus. Like modern corn (maize) it is very important to maintain wild populations of these valuable food crops. Through centuries of selective breeding, some of our important food plants have become vulnerable to climate change and diseases because vital survival genes may have been lost. Failure of these important food crops could be disastrous to human populations. Genes from wild plants may save many of our modern cultivated crops.

The cultivated banana is often listed in botanical references as Musa x paradisiaca (Musaceae), although it is actually a complex hybrid derived from two diploid Asian species, M. acuminata and M. balbisiana. Common cultivated bananas are usually triploid (3n) with three sets of chromosomes. [Note: The word "set" is defined here as one haploid set of chromosomes.] Like most other animals, humans are diploid (2n) with 2 sets of chromosomes, one paternal set from your father and one maternal set from your mother. The 2 sets pair up during synapsis of meiosis. Like seedless watermelons and red grapes, bananas are sterile and do not produce mature seeds. [Sometimes you can find aborted ovules inside the fruit that appear like tiny black dots.] Bananas are sterile and seedless because they are odd polyploids in which one set of chromosomes (A or B) has no homologous set to pair up with during synapsis. Therefore meiosis does not proceed normally, and viable gametes (sex cells) are not produced. Since banana fruits (technically berrylike ripened ovaries) develop without fertilization they are termed parthenocarpic. Without viable seeds, banana plants must be propagated vegetatively (asexually) by planting corms, pieces of corms or sucker sprouts.

Bat experts have launched a campaign, "Don't Blame Bats", to dispel unfounded fears and myths about bats, which are threatening their conservation. Bats are some of the most misunderstood and undervalued animals on the planet. Long the target of disdain, persecution and cultural prejudice, they have been blamed for a host of evils. Fears and myths about bats have only intensified since the COVID-19 pandemic.

Bat Conservation International: Facts About Bats

1. Bats are the only mammal capable of true flight.

2. Insect-eating bats may save US farmers $3.7 billion each year by reducing crop damage.

3. Hundreds of plant species rely on bats for pollination.

4. Bats are under unprecedented threat from habitat destruction, climate change, hunting and other pressures.

Nocturnal Flowers Pollinated By Bats

Sea Beans: Tropical Lianas (Mucuna sloanei)


A & B: Flower cluster of Mucuna (cf. M. sloanei) in the Monteverde Cloud Forest of Costa Rica. The long, rope-like stalk hangs below the forest canopy where night-flying bats can easily access the fragrant blossoms.

C: Velvety pods of another bat-pollinated sea bean (Mucuna) hang from long, ropelike stems in the rain forests of Belize. The hard, black seeds are called "ojo de buey" (eye of the steer) and "ojo de venado" (eye of the deer) by local residents. I originally concluded this was Mucuna argyrophylla; however, an updated flora of legume species in Belize lists M. holtonii rather than M. argyrophylla.

A. Pods and seeds of Mucuna (cf. M. sloanei) from the Monteverde Cloud Forest of Costa Rica. One seed has an attachment stalk (funiculus) that encircles the seed along its hilum. B. Pod and seeds of Mucuna near Golfito on the humid Pacific coast of Costa Rica. The pods are covered with dense, glistening, stinging hairs.

  Sea Beans: Lianas Of The Tropical Rainforest  

A bat visiting the blossoms of Mucuna sloanei in the Monteverde Cloud Forest of Costa Rica. Photo by Dr. Richard LaVal of the Bat Jungle, Monteverde, Costa Rica.

  The Bat Jungle At Monteverde, Costa Rica  

Sausage Tree (Kigelia africana syn. Kigelia pinnata)

The bignonia family (Bignoniaceae) is a fascinating tropical family containing many vines, trees and shrubs with beautiful, showy blossoms. Some of the well-known members of this family include cape honeysuckle (Tecomeria capensis), yellow bells (Tecoma stans), jacaranda (Jacaranda mimosifolia), common catalpa (Catalpa bignonioides), desert willow (Chilopsis linearis), African tulip tree (Spathodea campanulata), and the golden and pink trumpet trees (Tabebuia chrysotricha and T. impetiginosa). Also in the family is the unusual calabash tree (Crescentia cujete) with remarkable cauliflorous fruits that develop directly from the main trunks and limbs. But one of the most unusual trees in this family is the South African sausage tree (Kigelia africana), with huge sausagelike fruits that hang down from the limbs on long, ropelike stalks. The positioning of the noctural blossoms below the dense branches and foliage makes them ideally suited for visits by night-flying bats.

An interesting characteristic of the sausage tree flower is the thigmosensitive stigma which opens, closes and re-opens in response to touch and a sufficient amount of pollen (M. Raina, R. Kumar, & V. Kaul. 2017. "Stigmatic Limitations On Reproductive Success in a Paleotropical Tree: Causes and Consequences." AoB PLANTS 9: plx023; doi:10.1093/aobpla/plx023. Thigmotropic stigmas occur in other members of the bignonia family (Bignoniaceae), and also in other plant families, a good example of convergent evolution (homoplasy). Using the term homoplasy avoids the confusing distinction between parallel and convergent evolution. I have attempted to explain this on my evolution page.

  Homoplasy: Convergent & Parallel Evolution  

Thigmotropic stigmas are reported in at least 4 different plant families (red asterisks) as shown in left image modified from inside cover of Jepson Manual of California Vascular Plants (2012). They all have a common ancestor and are closely related. Is this an example of convergent or parallel evolution? I do not know if thigmotropic stigmas also occur in distantly related families. Thigmotropic tendrils certainly occur in many different and distantly related plant families and are a classic example of convergent evolution.
The distinction between convergent and parallel evolution usually assumes that when a given phenotype evolves, the underlying genetic mechanisms are different in distantly related species (convergent) but similar in closely related species (parallel). However, the same phenotype might evolve among populations within a species by changes in different genes, or it might evolve in distantly related species by changes in the same gene. So, the distinction between these terms may no longer be valid.

We have a native shrub in the local coastal sage scrub east of Palomar College with thigmotropic stgmas. Regarding the adaptive advantage of spreading stigma lobes that close together with the slightest touch of your finger or an incoming pollinator: This action decreases the chance of self pollination and favors cross pollination, especially if the incoming pollinator is covered with pollen from another monkey-flower blossom. When the bill or head of the hummingbird enters the blossom and touches the stigma it immediately closes. Pollen carried by the bird is trapped within the closed stigma lobes. As the bird probes for nectar deep in the corolla it also picks up fresh pollen from the anthers. But when it leaves, there is little chance of this newly acquired pollen touching the stigma because it is already closed, thus averting self pollination. Based on the above reference by M. Raina, R. Kumar, & V. Kaul (2017), the mechanism in sausage tree blossoms appears to be more complicated. A sufficient amount of pollen on the stigma lobes is required to initiate the closing process. "A threshold number of pollen grains is required to be deposited on the stigma to enable permanent closure of its flaps. ... We draw attention to the fact that fertilization in this species is conditional and subject to a critical pollen load deposition on the stigma."

M. Raina, R. Kumar, & V. Kaul. 2017. "Stigmatic Limitations On Reproductive Success in a Paleotropical Tree: Causes and Consequences." AoB PLANTS, Volume 9, Issue 4, July 2017, plx023 Get This Article On-Line

Red Bush Monkeyflower In Coastal Sage Scrub
  Thigmotropic Stigma Of Devil's Claw (Proboscidea)  

The blood-red flowers of the South African sausage tree (Kigelia africana) bloom at night on long, ropelike stalks that hang down from the limbs of this tropical tree. The fragrant, nectar-rich blossoms are pollinated by bats, insects and sunbirds in their native habitat. The mature fruits dangle from the long stalks like giant sausages. They may be up to two feet long and weigh up to 15 pounds. The white stigma lobes are open in far right image.
Fruits of the South African sausage tree (Kigelia africana) dangle from long stalks like giant sausages. They may be up to two feet long and weigh up to 15 pounds each.

Sausage Tree On Campus Of Palomar College: A Botanical Garden

Flowers of sausage tree (Kigelia africana) on Palomar College campus showing open & closed thigmotropic stigmas, and dehiscent anthers. Touch and sufficient pollen on the receptive stigma lobes initiates the closing process. The pollen-laden head of a bat is well-positioned to initiate this process. The honey bee in right image is obviously not a good pollinator of this species.

Flower of sausage tree (Kigelia africana) with corolla and stamens removed. Floral nectaries surrounding the base of ovary secrete copious nectar. There was a pleasant odor in my home office the following morning where I was photographing the flowers. Some authors describe the aroma as "fetid."

Long, rope-like flower stalks of sausage tree (Kigelia africana) hang from the branches. The large flowers are easily accessible to bats. Photograped on Palomar College campus 1 October 2021.

Calabash Tree (Crescentia cujete)

Any discussion of the bignonia family (Bignoniaceae) would be incomplete without mentioning the remarkable calabash tree. There are two species that grow wild in Mexico, Central and South America, Crescentia alata and C. cujete. Crescentia alata is often placed in the genus Parmentiera and is listed as P. alata. Crescentia cujete is easy to identify because it has simple leaves and its gourd-like fruits are much larger (up to ten inches in diameter). Both species belong to the bignonia family (Bignoniaceae), along with Catalpa and Jacaranda, and their flowers develop from buds that literally grow out of the main trunk and limbs. Like many other large-flowered cauliflorous species, calabash trees are commonly pollinated by small bats of the genera Glossophaga and Artibeus. The bats are attracted to the flowers by a slightly rotten odor. One possible reason for cauliflory in calabash is that it has co-evolved to aid its pollinator. The placement of the flowers on the trunk and main lower branches means that the bats do not have to navigate the foliage in order to pollinate the flowers–they are given easier access. According to Daniel Janzen (Costa Rican Natural History, 1983), the pollen is in the dorsal (upper) side of the flower and is placed on the head and shoulders of the bat. After pollination the spectacular calabash fruits begin to develop along the trunk and limbs. A crop of 100 or more of these large, green, gourd-like spheres may adorn the tree for up to seven months, before turning yellow-green and eventually falling to the ground. On the lovely Caribbean island of Dominica, Carib Indians carve elaborate designs into the woody gourds during this "softer" green stage. Because the gourds are so large and hard-shelled, no native New Word herbivores can crack them open, and the rotting gourds litter the ground beneath old calabash trees. It is well documented that horses can break open the hard shell with their mouth and eat the sweet pulpy mass inside, dispersing the seeds in their dung. In Africa, large woody pods of other species are quickly devoured by large herbivores. According to D.H. Janzen and P.S. Martin (Science Vol. 215, 1982), large grazing mammals, including extinct pleistocene elephants called gomphotheres, may have once eaten the huge gourds and dispersed the seeds in lowland forests.

The bat-pollinated flowers and large, gourd-like fruits of the calabash tree (Crescentia cujete) literally grow out of the trunk of this striking tropical American tree.

Cannonball Tree (Couroupita guianensis)

The canonball tree (Couroupita guianensis), a member of the tropical family Lecythidaceae, is native to the Guianas in northeastern South America. The large, fragrant blossoms develop on woody stalks that push right out of the thick bark and have no connection with the foliage at the top of the tree. Spherical, cannonball-like fruits are up to 8 inches in diameter, and often remain attached to the tangled flower stalks. Like many other fascinating trees of the tropical rainforest, this species is cauliflorus. Bees & other insects may visit the blossoms during the day, but according to the National Tropical Botanical Garden, Kauai, Hawaii, they are also pollinated by bats at night.

Saguaro Cactus (Carnegiea gigantea)

Saguaro cactus (Carnegiea gigantea) in bloom at Lost Dutchman State Park, Arizona. These blossoms are visited by the lesser long-nosed bat (Leptonycteris yerbabuenae).

  Lesser Long-Nosed Bat by Merlin D. Tuttle  

Jumping Cholla In Joshua Tree National Park
Beware--Even If You Are A Bat That Is Attracted To Cactus Blossoms!

Closeup microphotography with a scanning electron microscope (SEM) reveals why the spines of jumping cholla are so tenacious and difficult to pull out of skin. The spine is covered with sharp, overlapping scales or barbs that lie flat and allow the spine to penetrate skin readily like a very sharp needle. When you try to remove a spine, you are pulling against hundreds of tiny scales. In the process, other spines penetrate the skin from all directions, making the extraction very painful and seemingly hopeless.

Close-up view of the spine shaft from jumping cholla (Opuntia bigelovii) as seen through a scanning electron microscope (350 x). The numerous, sharp scales or barbs show why the spine is so difficult (and painful) to pull out.

The easily fragmented stem segments of jumping cholla are one of nature's most effective methods of hitchhiking and vegetative reproduction. Thickets of jumping cholla covering entire hillsides or alluvial fans may have developed from fragmented stem segments that became rooted in the desert soil. Although jumping cholla produces flowers, the seeds of most populations are typically sterile and reproduction is accomplished without sexual reproduction (technically referred to as apomixis). You could say that jumping cholla is a master in the art of hitchhiking and cloning itself.

Treacherous & Hopeless Encounter: A Bat Impaled On Jumping Cholla

Tropical Figs (Ficus): Important Food For Bats

The Asian Roxburgh Fig (Ficus auriculata) with large, cauliflorus syconia.

The distribution of 830 species of Ficus are shown in the green area of above map. Figs occur throughout the Old and New World tropics, extending north to the eastern Mediterranean and China. By far the majority of species are evergreen. The common fig (Ficus carica) is deciduous and grows in colder climates of Turkey and the Middle East. With the exception of the Hawaiian Islands, practically every tropical continent and major island group has one or more species of indigenous fig. In fact, the tiny island of Barro Colorado in the Panama Canal Zone, with an area of only six square miles, has 17 native species. Virtually every species of fig has its own unique species of "in house" wasp pollinator. The wasps are housed throughout the year inside the fig's hollow syconia, in one of nature's most remarkable symbiotic relationaships between a tree and an insect. The symbiotic wasps undoubtedly play a major role in the ability of different fig species to grow in the same locality, a phenomenon known as "species packing." Because they are an important component of tropical rainforests, fleshy fig fruits (syconia) are an important food source for some species of bats. Bats disperse the tiny seeds in their droppings on branches of other trees. In fact, this is how epiphytic strangler figs get started, sending anastomosing aerial roots to the ground and eventually taking over and shading out the host tree.

  Strangler Figs & Banyans Of Tropical Rainforest