CRICKETS AND TEMPERATURE

CRICKETS AND TEMPERATURE

 

One important aspect of behavior is communication, which is widespread among animals. Ask the students the following questions - How do humans communicate? Can insect talk? How do you think insects communicate?

 

Today we will learn about how insects communicate through sound production. There are many different ways that insect produce sound.

 

1. Stridulation - this is the moving of one body part against another.Some insects rub their wings together, others rub different segments of their abdomen. Some rub their legs and their wings, while others rub their legs against their head or their wings against their body. The most well known insects that use stridulation to produce sound are the crickets (rub their wings together) and grasshoppers (rub legs or leg and wing), but some ants, wasps, and beetles also use stridulation. Show examples, short-horned grasshoppers, long-horned grasshoppers, bess beetles

 

2. Strike a part of the body against a surface - deathwatch beetles tap their heads, cockroaches and some stoneflies tap the tip of their abdomen, and some grasshoppers tap their feet against a substrate to make noises.

 

3. Vibrating membranes - cicadas, which make very distinctive sounds vibrate tymbals. Tymbals are membranes located on the abdomen that are moved by muscles. Other insects make sounds by vibrating their wings or other body parts.

 

4. Forcing air through body openings - although many vertebrates use the expulsion of air to make sounds (as we do when speaking), this form of communication is fairly uncommon among insects. Some cockroaches make a hissing sound by ejecting air. The death's head sphinx moth expels air to make a whistling sound.

 

Why do insects make sound? Insects often use sound to communicate with each other. Most often, insects produce sounds to attract mates. Usually, the male's song attracts the female. Often, insect will make noise when they are disturbed - this may be to scare off the predator or to warn other insects of danger. Some insects use sound to mark their territory. A male insect may sing in order to let other males know that an area is his territory.

 

What is a disadvantage of stridulation. Predation - you let everyone know where you are!

 

How do insect detect or hear these sounds? Crickets, grasshoppers, katydids, and cicadas all possess hearing organs called tympanum. The tympanum is located on the front legs of crickets, katydids, and long-horned grasshoppers and on the abdomen of short-horned grasshoppers.

 

Temperature Inquiry:

 

Background:

Male crickets and katydids chirp by rubbing their front wings together. Each species has its own chirp and chirping is temperature dependent. Crickets chirp faster with increasing temperature and slower with decreasing temperatures. Therefore, at least in theory, the temperature can be estimated by counting the chirps. However, problems with putting this theory into practice abound. For example: (1) crickets generally do not sing at temperatures below 55 F or above 100 F, (2) some crickets do not chirp in discrete bursts, they utter a more continuous trill, (3) chirp rate is affected by other factors such as the cricket's age, mating success, hunger, and with competition from nearby males. Nevertheless, this is a fun inquiry to do.

 

Methods:

The simplest method is to count the number of chirps in 15 seconds and add 40. The sum usually approximates the temperature within a few degrees Fahrenheit.

 

The original formula for determining temperature from cricket chirps appears to have been published in 1897 by A.E. Dolbear, a physics professor at Tufts College. Since Dolbear's time, formulas have been devised for various species.Here are Three formulas which may or may not actually work! In all cases, T is the temperature and N is the number of chirps per minute.

 

Field Cricket: T = 50+[(N-40)/4]

 

Snowy Tree Cricket: T = 50 + (N - 92 / 4.7)

 

Katydid: T = 60 + (N - 19 / 3)

 

Additional Notes:

This exercise may be done whenever crickets are heard, either in the field or with classroom cultures.

Entomology News at Nebraska

Breaking Entomological News...

  • Dr. Susan WellerDr. Susan Weller, director of the University of Nebraska State Museum and professor of Entomology, has been elected a fellow of the Entomological Society of America (ESA). The society noted Weller’s internationally-known research on arctiine moths and other Noctuoidea, and her administrative leadership in promoting entomology and science education. See the article at UNL News for more about Weller's recognition. Congratulations Susan!
  • Marilyn Weidner & GracieWe are pleased to announce that Marilyn Weidner has been named winner of the IANR Exemplary Service Award! Weidner has roles in administrative support, personnel management, data documentation and archiving, review preparation, promotion and evaluation tracking, payroll for 15 departments, and much more. Well deserved Marilyn!
  • Rogan Tokach winning scholarshipCongratulations to Rogan Tokach (Master's student co-mentored by Dr. Autumn Smart and Dr. Judy Wu-Smart) on being awarded a $10,000 national Christi Heintz Memorial Scholarship by Project Apis m!
    Well done, Rogan!
  • Steve Spomer with Beetle CollectionsSpomer nets 40-year Butterfly & Beetle Legacy. Best wishes to Steve Spomer who is retiring this December after 40 years in the Entomology Department. Spomer has identified nearly 700 insect species, including the Salt Creek Tiger Beetle, and taught countless University of Nebraska-Lincoln students. 
  • Bridget Gross with Bees.Bridget Gross, master's student in Entomology, mentored by Dr. Judy Wu-Smart and Dr. Doug Golick, was featured in the Nov. 11th IANR Student Spotlight. Bridget presented her master's degree seminar last month and graduates in December.

  • Check out the Emerald Ash Borer Resource Center, and our Emerald Ash Borer Look-Alike Insects Sheet - Be Sure Before You Treat!