A soldier sleeps under the thickening tropical vegetation. A mosquito net enshroud his head.

In the era of human-induced climate change, insects have become the preeminent emissaries of Death, morphing the proverbial scythe into tiny tentacles of destruction. The invasion of tropical insects into the Global North has emerged as a key narrative template of the climate apocalypse: articles in scientific and journalistic outlets register the harrowing threat of climate change not only as the sublime terror of melting ice caps or as the urban noir of smoggy metropolises, but also in the rather abject terms of insects swarming into the good life (Houtman et al., November 10, 2022; Colón, October 27, 2022; Van Note, March 15, 2023).

The tropics continue to be the locus of global pestilence. The emerging as well as the expanding forms of tropical pestilence in the warming planet are all zoonotic diseases (West Nile, Zika, dengue fever, malaria) carried by insect vectors, making mosquitoes, fleas, and ticks emblems of the encroachment of the tropical South into the temperate North. Are these insect vectors then coming to replace the “human carriers” (4) that Priscilla Wald presciently identified as the animating agents of “the virus” in the “outbreak narrative” (2)?

The invasion of these malicious tropical insects parallels the disappearance of the bees and the midges, the insect arbiters of the global food chain and temperate livelihoods. The environmental journalist Oliver Milman captures the pathos of the imminent decay of the Global North lifeways in the era of what he calls The Insect Crisis, suggestively subtitled The Fall of the Tiny Empires that Run the World (2022):

The disappearance of cecidomyiid and ceratopogonid midges, the unheralded pollinators of the cacao tree, cut off the supply of chocolate. People openly wailed in the streets at this loss; rates of depression and anxiety soared…Still, meals became blander and less nutritious, even in wealthy countries…With no chilies, cardamoms, coriander, or cumin, curries became a historical dish. (Chapter 1)

The book’s emphasis on the importance of insects in sustaining human life is commendable. That said, any reckoning with how colonialism and capitalism (except for one wishy reference to “colonial voyages”) propel anthropogenic climate change remains starkly absent from the account.  Curries and chocolate seem to have miraculously appeared as tropical bounties in temperate supermarkets without the detour of colonial capitalism and without unleashing deadly insects in their wake. The waning of tropical delicacies and the surge of tropical insects therefore become historically unrelated phenomena in this account, merely connected through a sliver of jump scare. What is the genealogy of this horror story of tropical insects?

Historians of tropical medicine have long recognized the importance of the insect as a feature of the field itself, one which distinguishes it from the field of so-called “cosmopolitan diseases”. After all, in the second half of the nineteenth century, the scientific discoveries of the likes of Manson, Ross, Leishman, and so on focalized mosquitoes or ticks, rather than decaying vegetation or festering heat, at the causal core of tropical diseases (Moulin 160). However, as with the epitome of natural rot and moral corruption ceaselessly germinating in the uncultivated tropics, the insect has a much longer history of shaping the cultural imaginary of tropical pestilence; this history remains largely buried in the circulating strings of references across medical treatises and cultural periodicals, travelogues, and agrarian treatises.

As the philosopher and anthropologist of science Bruno Latour taught us, the crystallization of scientific concepts happens at the level of “circulating references” (53), enchaining a “regulated series of transformations, transmutations, and translations” (58). The trail of insect history ought to go through the putatively segmented but intersecting nodes of medical and cultural archives. I am calling this method of deciphering the conjoined body of seemingly disparate parts in the conceptualizations of the tropical insect entomopoiesis, where the Greek entomon, the neuter of entomos, perform the textuality of “cutting” across textual registers, while poiesis or “making” stage their conjugated interlinks, befitting the figure of the insect itself. These references crawl across continents as the following archival snippets bring South Asia, Europe, and South America together in showing us the sprawling monstrosity of the tropical insect.

In Influence of Tropical Climates (1861), the British military surgeon James Ranald Martin (very much a believer in the older understanding of malaria as a disease of “bad air”) eulogizes the virtues of the mosquito net in ensuring “complete protection from mosquitoes” (177) for retaining “rational faculties” in “temperate” (178) British bodies in the tropical subcontinent. Martin cites the Anglican cleric and writer Sydney Smith, a regular on the Edinburgh Review to underline the odious nature of tropical insects. As expressed in his 1826 review of the English naturalist and plantation overseer Charles Waterton’s Wanderings in South America (1825), the horror of the tropical insects lie in their felicity to burrow into polite British comportments:

Insects are the curse of tropical climates. The bête rouge lays the foundation of a tremendous ulcer. In a moment you are covered with ticks. Chigoes bury themselves in your flesh, and hatch a large colony of young chigoes in a few hours…Flies get entry into your mouth, into your eyes, into your nose…ants eat up the books…All nature is alive, and seems to be gathering all her entomological hosts to eat you up, as you are standing, out of your coat, waistcoat and breeches. (310)

Now, Waterton in his account does register the profusion of insects in tropical South America, “beautiful past description in their variety of tints, astonishing in their form and size, and many of them noxious in their qualities”, but this paradox materializes the riches of “uncultivated nature” for him (49). What the animal studies scholar Lucinda Cole notes in her magisterial account of the early modern “vermin” in Imperfect Creatures (2016) as the slithering capacity of this category to pose dangers to “agricultural and sociopolitical orders” (1) would seem to perfectly capture the tropical insect in their wreckage of imperial bearings. The narrative sinews of the tropical insect certainly draw upon the fibers of early modern “imperfect creatures” and their ability to spawn “a generalized system of pestilence“, at once natural, moral, and sociological (25).

And yet the tropical insect stands apart in its embodiment of both fertility and decay.  The Dutch philosopher and geographer Cornelius de Pauw’s highly influential natural history of the “New World,” Recherches Philosophiques (1771), translated in William Walton’s Present State of the Spanish Colonies and quoted in a wide corpus of texts of imperial improvement, plays a key role in textualizing this lure of the tropical insect:

[T]he surface of the earth is infected by putrefaction, is over-run with lizards, serpents, reptiles, and insects of a monstrous size, deriving the activity of their poison from the copious juices of this uncultivated soil, which being corrupted and abandoned to itself, the nutritive juice became sharp like the milk in the breasts of animals which do not exercise the function of propagation. (103)

He consigns specific insects to Panama, Mexico, Suriname, and other sites in South America—the putatively “uncultivated” spaces waiting to become important nodes in the temperate consumption of tropical treats over the next few centuries. Evidently, far from being a recent crisis, the tropical insect has been crawling through the longue durée of the imperial capital.


Works Cited

Cole, Lucinda. Imperfect Creatures: Vermin, Literature, and the Sciences of Life, 1600-1740. University of Michigan Press, 2016.

Colón, Felipe. “World at risk: how malaria, dengue could spread due to climate change.” https://wellcome.org/news/world-risk-malaria-dengue-spread-climate-change

Houtman, Jacqueline et al. “The Increasing Fever of Dengue Fever in a Changing Climate”. https://www.rockefellerfoundation.org/blog/the-increasing-burden-of-dengue-fever-in-a-changing-climate/

Latour, Bruno. Pandora’s Hope: Essays on the Reality of Science Studies. Harvard University Press, 1999.

Martin, James Ranald. The Influence of Tropical Climates in Producing the Acute Endemic Diseases of Europeans. John Churchill, 1861.

Milman, Oliver. The Insect Crisis: The Fall of the Tiny Empires that Run the World. Atlantic Books, 2022.

Moulin, Anne Marie. “Tropical without the Tropics: The Turning Point of Pastorian Medicine in North Africa”, in Warm Climates and Western Medicine: The Emergence of Tropical Medicine, 1500-1900, edited by David Arnold, pp. 160-180. Rodopi, 1996.

Note, Sara Van. “West Nile, Lyme, and other diseases are on the rise with climate change. Experts warn the U.S. is not prepared.” https://www.statnews.com/2023/03/15/climate-change-diseases-west-nile-dengue-lyme/

Smith, Sydney. “Art II: Review of Wanderings in South America”, The Edinburgh Review Vol XLIII, November  1825- February 1826. Printed by heirs of D. William, 1826.

Wald, Priscilla. Contagious: Cultures, Carriers, and the Outbreak Narrative. Duke University Press, 2008.

Walton, William. Present State of the Spanish Colonies Vol II. Longman, Hurst, Rees, Orme, and Brown, 1810.

Waterton, Charles. Wanderings in South America. Cassell & Company Limited, 1891 (1825).







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