Nature's Neighbors ~ Honey Mesquite

Honey Mesquite is a common shrub/ small tree of the Southwest. Some specimens can grow to larger size, especially if growing in moist bottomlands.  Like many other members of the legume family, mesquite beneficially restores nitrogen to the soil.

Mesquites are deciduous and have characteristic bean pods which have long been used by humans, wildlife and livestock as a food source. It is estimated that over 75% of a Coyote's diet in late summer is mesquite beans. It is an extremely hardy, drought-tolerant plant because it can draw moisture from the water table through its long taproot, one of which was found in an underground copper mine 190 feet below ground!  It can also use water in the upper part of the ground through it’s shallow subsurface roots, depending upon availability. The tree can easily and rapidly switch from using one water source to the other. 

small specimen in arid cimate

Cattlemen regard mesquite as range weeds and eradicate them. But much of the invasion of mesquite into former grasslands where it did not grow a century ago, is ironically, due to the overgrazing of domestic cattle.  By contrast, this versatile tree has long been a welcome presence in the larders, livestock feed bins, workshops, gardens and medicine cabinets of many desert residents. 

During the inevitable droughts and deprivations of desert frontier days, the mesquite trees served up the primary food source for caravans and settlers.  During the Civil War, when groceries often ran short, mesquite beans served as passable coffee. The beans were also durable enough for years of storage and became the livestock feed of choice when pastureland grasses failed due to drought or overgrazing.  Native Americans relied on the mesquite pod as a dietary staple from which they made tea, syrup and a ground meal called pinole. They also used the bark for basketry, fabrics and medicine. Mesquite blooms, pollinated by bees, yield a very tasty honey (hence the name Honey Mesquite) and feed adult butterflies.  The leaves serve as food for butterfly larvae.

large tree near a waterway

Although often crooked in shape, mesquite tree branches, stable and durable, filled needs for wood during the construction of Spanish missions, colonial haciendas, ranch houses and fencing.  Artisans use it in the crafting of furniture, flooring, paneling and sculptures, and in some areas mesquites provide a bountiful harvest of wood for use in fireplaces and barbecue grills.

So weather you see them as an uninvited interloper or welcome neighbor, the mesquites have proven that they belong in the Southwest.

Nature's Neighbors ~ Mexican Free-tailed Bat

Mexican free-tailed bats are a medium-sized bat with short, velvety, reddish to black-colored fur, broad ears, large feet, and the end of its tail extending beyond the edge of it’s tail membrane, hence the name “free-tailed”.  They occupy a wide variety of habitats, ranging from desert communities through pinion-juniper woodland and pine-oak forests, at elevations from sea level to 9,000 feet or more. The largest U.S. populations of free-tailed bats live in the West.  The densest concentrations are found in Texas where they form maternity colonies which are found in limestone caves, abandoned mines, under bridges, and in buildings, but smaller colonies also have been found in hollow trees. It is estimated that 100-million Mexican free-tailed bats come to Central Texas each year to raise their young, the largest colony is currently found living in Bracken Cave near San Antonio, Texas, totaling over 20 million.  Nursing females require large quantities of insects that are high in fat, which they obtain by consuming egg-laden moths.

The 100 million free-tailed bats living in Central Texas caves consume approximately 1,000 TONS of insects each night.  Researchers use Doppler weather radar to watch emerging bats ascend to altitudes of 1,000-10,000 feet to feed on migrating cotton boll worm moths, army cut-worm moths, and other costly agricultural pests that migrate north from Mexico. These migratory moths hopscotch across the country each year, reaching rich agricultural land as far north as the Canadian border. The cotton boll-worm moth (a.k.a. corn ear-worm moth) alone, costs American farmers a billion dollars annually.   Although the ecological and economic impacts of large colonies are most obvious, even small colonies of bats can significantly impact local insect populations. Mexican free-tailed bats also consume enormous quantities of insects over woodlands and forests, likely including many additional pests.  

The impact of second hand pesticide poisoning of free-tails and other bats should not be underestimated, but it seems certain that this is probably not the major stress responsible for the decline of free-tailed bat populations. In a recent review of the effects of environmental contaminants on bat populations, it seems quite evident that much of the decline in free-tailed bat populations is directly due to human disturbance and roost site destruction.  It is important to preserve those colonies which still thrive. The apparent good condition of several large roosts is clearly due almost entirely to the fact that access to them is restricted by land owners who appreciate the unique resource with which they are entrusted.

Current initiatives by Bat Conservation International, The Nature Conservancy, and the Marbach family to ensure continued protection of the site of the largest known roost in Bracken Cave are to be applauded.

So the next time that you bite into that juicy ear of corn or ripe apple, remember a bat probably  played a part in bringing it to you!

Nature's Neighbors ~ June Beetle

Ever seen a hairy beetle before?  You probably have, but don’t realize it!

The "June Bug" (or May Beetles as some call them) is a member of the scarab beetle family which has approximately 1375 species in North America.  On warm spring and summer nights, these beetles are famous for bumping into your porch lights, or you if you get in the way of their clumsy flying.

They are nocturnal, but during the day they hide in the shade of leaf litter, in cracks or under things on the ground around your home to stay cool and out of sight of lizards and birds, their main predators.  The adults are  ½ to 5/8 inches long, reddish brown in color and feed on the foliage of trees and shrubs.  White "C"-shaped larvae (grubs), are up to 1 inch long, with cream-colored bodies and brown head capsules and feed on the roots of grasses and other plants.

The insects pupate (change from grub to beetle) underground in the fall.  There is one generation per year, but in colder climates, development may take two years. Adults begin to emerge in spring. During adult flights large numbers of beetles can be attracted to lights. Peak flights occur in mid to late June in central Texas, but if the weather is warm, you will start to see them as early as March.  They may cause significant plant damage if they emerge in large numbers.    

Humans who go to great pains to have “perfect” lawns may consider them a pest species, as the larvae can damage turf grasses, but as far as their natural predators in the food chain are concerned, they are irreplaceable as a food source!