Something Fishy in the Nest

By Neff, Bryan D. | Natural History, February 2004 | Go to article overview

Something Fishy in the Nest


Neff, Bryan D., Natural History


In many fish species, dad does the caregiving. But some sneaky bluegill males have ways of avoiding the responsibilities of fatherhood.

Questions of fatherhood are a staple of dramatic conflict, whether in Greek tragedy, soap opera, or divorce court. In the natural world, too, conflicts brought on by uncertain paternity have opened up rich veins of phenomena for scientific investigation. Behavioral ecologists, who study how natural selection shapes animal behavior in light of ecological and social conditions, have long grappled with the role that parentage-genetic relatedness-plays in how much care fathers provide their young.

A fundamental principle of adaptation, growing out of Darwin's theory and elaborated in recent times by several prominent evolutionary biologists, is that individuals promote the spread of their own genes over the genes of competitors. The degree to which a male is sure he has sired offspring, then, should influence how much time and energy he invests in caring for them. To what extent that prediction might apply to human beings is a matter of debate; even tor other animals, confirming it proves to be tricky.

DNA testing can determine who sired whom, but does the outcome of a DNA test really overwhelm other factors, such as parental age or number of offspring, that affect the time and energy an adult animal devotes to caretaking? Geneticists can determine family relationships via DNA fingerprinting, but can the males of animal species identify their young, and if so, how? And how much does care of the young by the biological parent matter anyway, so long as the genes of the parent survive? Those questions have intrigued me for more than a decade. Recently some answers have been emerging from work with a common freshwater fish I've found to be a finned exemplar of Shakespeare's line from The Merchant of Venice: "It is a wise father that knows his own child."

The bluegill sunfish (Lepomis macrochirus), a social, schooling species popular with anglers, is endemic to the freshwater lakes, ponds, and rivers of North America. The fish are particularly prolific in lakes with relatively shallow, warm water and plenty of weedy vegetation. Males, which are about 25 percent larger than females, range from eight inches long in southern Canada to fourteen inches in the southern United States. Young bluegills eat mainly zooplankton, but as they grow older, they become opportunistic and devour almost anything that fits into their mouths.

In bluegills, as in many other fish species, only the male cares for the offspring. During the summer breeding season, adult males called parentals venture near the shore of a lake, where they collect in colonies that may have hundreds of members, all ready to reproduce. The parental males fight fiercely for nesting sites in the center of the colony-in part because those locations provide the best available protection against such egg-feeding predators as catfish. Not surprisingly, the largest males usually secure the most central positions.

After staking out a spot, parental males construct nests by sweeping a bowl-shaped depression in the lake bed with their tail fins. Nests are about the size of large dinner plates and are positioned right next to one another in the crowded colony site. It takes a few days for the colonies to form. Once all the males have selected sites and built their nests, the general commotion subsides and the parentals await the females.

Then they arrive. A school of females that can number in the hundreds swims in, above the colony. What they look for in a mate is not yet known. But they do seem choosy, passing up numerous nests and potential mates before accepting one. Evolutionarily, of course, selecting a mate is critical: the offspring will not survive without proper care from a parental male. Yet once spawning begins, it lasts just a day-though it can recur several times in a season. During the day of spawning a female tilts her body and releases a spurt of about thirty eggs into a male's nest, a behavior known as a "dip. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Something Fishy in the Nest
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Author Advanced search

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.