Singing Insects:  Grasshoppers, Crickets, Katydids

Grasshoppers, Crickets, and Katydids are members of the Orthoptera, one of the most familiar insect orders.  Orthoptera is divided into two suborders: Caelifera (grasshoppers and relatives) and Ensifera (crickets, katydids, and gryllacridoids).  Cicadas (locusts) are also singing insects, and they are common in the Agua Fria River Basin.  Cicada distribution maps and sound recordings are being placed on the Internet.  I will post references to the information when it is available.

The katydid in the photo is probably Greater Angle-wing Katydid (Microcentrum Rhombifolium), or Gawk.  The California Angle-wing (Microcentrum californicum) also occurs in the Agua Fria River Basin, and according to the BugGuide website the two are distinguished chiefly by their songs.  The songs are quite distinctive.  Next time I see this Katydid I will try to catch a few notes to compare to the MusicOfNature recordings.

Loggerhead Shrikes (Lanius ludovicianus) are fairly common in the Agua Fria River Basin, but the one shown here is the first one I have photographed.  This fellow was quite curious about me, and while I stood talking to him, fluttered to within about ten feet, then perched nearby while I tried for a good camera angle.

Male and female shrikes share the same white,  gray, and black plumage, and both parents feed their young.  This big-headed little bird hunts insects and small lizards, mammals, and birds from fences, trees, and shrubs.  Shrikes have strong beaks but relatively weak talons.  When they make a catch they carry their prey to a thorny tree or shrub, impale it, and tear it asunder with their powerful beaks.  If prey is plentiful, some will be left impaled for later use.  These ‘left overs’ are perhaps used to mark territory and attract females.

Loggerhead Shrikes have declined throughout the United States, especially in the Midwest and Northeast.  Breeding bird surveyors (Corman and Wise-Gervais 2005) found the bird nesting throughout Arizona, but according to Sauer et al. (1995), there has been a measurable decline.  Roads, pesticides, and other threats are discussed by Julie Craves (2007).   Shrikes prefer open woodland and shrubland with abundant perches and thorny plants.  As these habitat types fade away due to the spread of invasive weeds and the increase in wildfires, shrikes will become scarce.  But until the chaparral is burnt out and the megapolitans arrive with their bulldozers, you can see these unusual little birds just about anywhere in the upper Agua Fria River Basin.

References (Look for additional references in the earlier post on Arizona Birds)

Corman, T.E., and C. Wise-Gervais. 2005. Arizona breeding bird atlas. University of New Mexico Press, Albuquerque, NM.  636 p.

Craves, J.  2007.  Species profile: Masked predator, Loggerhead Shrike.  Birdwatching.  August 22, 2007.  Online in the bird profiles section at:  http://www.birdwatchingdaily.com.  (On the BirdWatchingDaily website go to ‘getting started–bird profiles–August 2007 edition.)

Sauer, J.R., S. Orsillo, and B.G. Peterjohn.  1995.  Geographic patterns and population trends of breeding and wintering Loggerhead Shrikes in North America.  Proceedings of the Western Foundation of Vertebrate Zoology 6: 128-141.

Arizona Ants

Ants are a critical component of the earth’s terrestrial ecosystems.  They consume and break down large amounts of material, they control the populations of numerous species, and they provide food for many others.  For instance, ants make up 40% of the diet of the Northern Flicker, a common Arizona bird.  Despite being small and not so visible, ants account for 15% to 25% of all animal biomass on our planet’s land surface—far more than any other animal group.

So how much do the ants weigh?  Using guesstimates from the references I made assumptions that the average ant weighs .004 grams, and that there are 1,000,000 ants per human.  Thus, the earth’s ants weigh around 21 billion tons.  Not to be beaten by these little bugs, however, humanity is increasing its weight at a rapid rate.  Issac Asimov once (Asimov 1975) estimated that if our numbers continued to grow at the 1970′s rate of 2% (doubling in 35 years), the mass of humanity would match that of the whole planet in about 1500 years.  Probably no ants (or any other animal) could survive this.  Of course, our birth rate is declining, and even though our life expectancy is increasing, doubling our numbers will take longer and longer.  If we assume that the average human weighs 120 pounds, our species currently weighs 420 million tons.  If we double every 100 years, and if we do not destroy any ant habitat (OK, that is not a reasonable assumption.  Nevertheless…), we would weigh more than the ants in 600 years.

The photo shows Myrmecocystus navajo, a member of the Formicinae subfamily.  This one was collected in Yavapai County, Arizona.  The photo may be by Barry Bolton, but it could be by Stefan Cover or Bob Johnson.  It is from the AntWeb website.