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Biography - Mary Treat

On September 7th, 1830, a child was born that would contribute greatly to the world of science, and promote the greatness of her gender. This child was named Mary Lua Adelia Davis. Davis moved often over the course of her lifetime. Her family moved from her birthplace in Trumansville, New York, to Ohio. In 1863, Mary Davis acquired her better known name, Treat, when she married Dr. Joseph Burrell Treat. In 1869, the couple moved to Vineland, New Jersey. Then, after Mary separated from her husband in 1874, she continued to move around for her scientific study, and sometimes changing her environment simply because she pleased.[1]

Mary Treat is most well known for her extensive work in botany and entomology. Her impressive work record includes countless scientific articles and a good number of books and other works. Treat began with publishing articles in scientific magazines such as Harper’s and Queen. She then made her own make by publishing her first article in The American Entomologist. Mary Treat’s work often hit home, studying plants and insects in her personal garden. Treat wrote in a way that made her audience feel included, differing much from other publications that have a conceded air about them since they are written by “experts”. The comfort of her works was added to by her inclusive dictation and her home-bound research.

While Mary Treat conducted her research on her own, and for her own benefit, she did take requests from her fellow scientists. Scientists would ask her to collect samples to aid in their studies.[2] Of her many correspondents, her most famous is a Mr. Charles Darwin. Mary Treat and Charles Darwin traded letters throughout the 1870’s. By reviewing these letters, one can see the wide diversity of Treat’s work. While mostly focusing on insects, Darwin and Mary’s conversation covered a wide range of species and also included plants. The first encounter of Treat and Darwin included a letter to Darwin from Treat discussing her research on flies and trying to determine the sex of the adult by the size of the larva. Darwin found Treat’s research respectable, and requested her conduct other research and supply him more information. Darwin and Treat traded knowledge back and forth. Treat gave him data that he could use for his future book The Origin of Species and Darwin repaid her with encouragement and publishing advice. Over the course of their partnership, Treat and Darwin exchanged a total of 15 known letters.[3]

Of Mary Treat’s extensive body of work, one remains less mentioned than the others. Treat’s Chapters on Ants does not receive reference in biographies on her research. This book documents Treat’s studies on two species of ants: slave-making ants and harvesting-ants of Florida. The two studies did not at first appear together.[4] In the beginning, Harper’s New Monthly Magazine published Treat’s “observations of the habits of the slave-making ants (Formica sanguine) of New Jersey”[5]. Treat later published her “paper on “The Harvesting Ants of Florida””[6] in Lippincott’s Magazine. This combination composition debuted in 1879.[7] The book divided into two sections, one for each species of ant. This publication also contains 14 illustrations that correlate with Treat’s research.[8]

Mary Treat’s Chapters on Ants begins with her study of the slave-making ants of New Jersey. The rest of my paper focuses on this chapter. This chapter looks in detail of the conquests of the slave making ants. She begins by describing her subjects: a type of red slave making ants. The ants “nest was in a grove that surrounds the house, and must have contained several thousand working inhabitants.”[9] The slave making ants, Treat noted, also often moved nests, taking their larva with them. Along with these ants, a species of black ants lived nearby in the same grove. Mary Treat describes their temperaments: the black ants proved much more docile while the red ants would bite anything that slightly disturbs their nest.

One morning, Mary writes, a war between the red slave-making ants and their black ant neighbors. Watching in “wonder and astonishment”[10], Treat observed that “a powerful army of red ants had invaded the domains of the black colony.”[11] The battle extended out of the black ant nest onto the surround ground. So many ants battled there that Treat could not move without crushing some. She watched for three hours before the sun forced her to move inside, but the battle still raged on. Mary Treat gathered some of the ants to study inside. She comments that the ants, so intently focused on their combat, did not notice her capture them. She watched 10 red ants and 10 black ants under a watch glass. Both ants fought greatly, but the red ants’ ferocity overtook the black ants. By morning, all black ants laid slain and few red ants remained. She describes the gruesome scene: “the legs and antennae and mutilated bodies of the warrior are strewn about.”[12]

Mary then leaves her home to see what the war outside left behind. At the nest, she sees no black ants, and only red ants plundering the black ant nest and taking their spoils back to their own abode. Red ants, after taking over an enemy, will take their young and turn them into slaves. Mary noticed that the red ants also carried bundles of adult black ants back to their nest. This goes against long standing belief that slave-making ants did not take adult hostages since they would not make good slaves.[13]

Mary goes on describing the wide conquests of the red slave-making ants. These ants go on battling and seizing many other tribes of ants: a colony of yellow ants, another nest of black ants, a population of larger species of black ant, and more. Each battle is slightly different. This different species of black ant, Treat wrote, simply ran when invaded by the red ants, so little carnage came from this encounter. The red ants excavated this nest in a similar manner, taking larva and pupae and some adult ants. Their victims then became slaves for the red ants. Mary also took note that the slaves never accompanied their red masters to battle.[14]

A colony of tiny yellow ants became the next victims of the slave-making ants. The red ants hardly had to fight these species because of their small stature. This caught Treat’s curiosity. She could not figure out why the red ants would want to invade this colony, since they would have little use as slaves. After a couple days, she found her answer. Larger female ants, even larger than the red ants themselves, dwelled farther within. The red ants took these ants as hostages.[15]

At the same time, the red ants attack a colony of large colony of brown ants. These brown ants fought very differently. They did their best to rescue their larvae. Nurse ants would carry them out of the nest in their mouth and “mount a blade of grass or stem of a clover, and there they remain perfectly still, holding the pupa”[16] until the danger ended. This evacuation effort quite confused the red slave-making ants, often letting the nurses pass by. Eventually, the red ants captured some young and adults. The brown ants did not sustain as much damage as other populations due to the removal of the larva.[17]

The red ants encountered another enemy: a large yellow-brown ant with blacks heads and abdomen tip. The red ants did not attack this foe forthright. They hesitated, but then attacked the few individuals that stood outside the yellow-brown ant mound. After killing these few members, the red ants again hesitated. Instead of charging into the entrance, “they move around it excitedly.”[18] Mary, curious as to what was creating this behavior, uncovered the yellow-brown ant entrance more. Suddenly, “a solid black mass of heads rush to the front… and seize two soldiers and literally chew them up, and again retreat.”[19] This explained the red ants timid nature.[20]

Finally, Mary Treat wraps up this chapter with an explanation of the work within the red slave-making ant mound. Treat notes that the red ants change behavior in late August. They cease their crusades of other tribes and focus their activity towards the nest. They also seem to try and make their captives even more subject to their power. She observes an equal division of labor among the slave ants: the black ones “doing the principle work of excavation, while the brown and yellow ants are mostly the caterers and nurses.”[21] The calming of the red ants is evident when they encounter stranger ants, who come to their nest, attracted to their food. Red ants scare off the intruder, but not with intent to kill it. Along with the reduction of brutality towards neighboring ants, the slave-makers also treat their slaves less violently. When a slave wanders off, a red ant retrieves it. The wandering ant will submit, rolling up so that the master ant can take it back to its post. Finally, Mary Treat writes that the brown slave ants “proved to be a great trouble and annoyance to their masters.”[22] They behaved differently than the slave-making ants, making them of little use to the nest. Once such behavior included covering food they could not carry back to the nest.[23]

Mary Treat spent many years creating her wide arrange of impressive work. She traveled many different places and documented many species of both plants and animals. She dedicated her life to botany, for which she is now famous. Mary Treat settled down, retired, and went to live with her sister in Pembroke, New York. She lived here until she died. Mary died on the 11th of April, 1923 at the age of 92 from complications due to a fall. Mary Treat now lies in Vineland, New Jersey, where she spent much of her time living and conducting her beloved research.[24]

Jennifer Hollen

[1] Danuta Bois. “Mary Davis Treat” Distinguished Women of Past and Present (1999) http://www.distinguishedwomen.com/biographies/treat-md.html
[2] “Mary Lua Adelia Davis Treat” Wikipedia (February 18, 2012) http://en.wikipedia.org/wiki/Mary_Lua_Adelia_Davis_Treat
[3] University of Cambridge. “Darwin Correspondence Project” (2012) http://www.darwinproject.ac.uk/advanced-search?page=1&as-corresp=Treat%2C+Mary+&as-person=&as-place=&ask-content=&asv-content=as-body&as-year-from=&as-year-to=&as-set=&as-physdesc=&as-volume=&as-repository=&as-calnum=&as-n=&intercept=adv&asp-page=0&as-type=letter&asdesc=
[4] Mary Treat. “Chapters on Ants” (New York: Harper & Brothers, 1879) 7.
[5] Ibid., 7.
[6] Ibid., 7.
[7] Ibid., 5.
[8] Ibid., 10.
[9] Ibid., 13.
[10] Ibid., 15.
[11] Ibid., 15.
[12] Ibid., 19.
[13] Ibid., 19-20.
[14] Ibid., 36-39.
[15] Ibid., 41-43
[16] Ibid 46.
[17] Ibid., 44-46.
[18] Ibid., 51.
[19] Ibid., 51.
[20] Ibid., 49-51.
[21] Ibid 53
[22] Ibid 63.
[23] Ibid., 53-65.
[24] Danuta Bois. “Mary Davis Treat” Distinguished Women of Past and Present (1999) http://www.distinguishedwomen.com/biographies/treat-md.html


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