Henry Walter Bates FRS, FLS, FGS (February 8, 1825 – February 16, 1892) was an English naturalist and explorer who gave the first scientific account of mimicry in animals. He was most famous for his expedition to the Amazon with Alfred Russel Wallace in 1848. Wallace returned in 1852, but lost his collection in a shipwreck. When Bates arrived home in 1859 after a full eleven years he had sent back over 14,000 specimens (mostly insects) of which 8,000 were new to science.
Bates was born in Leicester
and, like Wallace, T.H. Huxley
and some other British scientists of the time, he had no formal education in science, and left school at 12. He came from a literate middle-class family and taught himself mainly by reading (like Wallace, Huxley and Herbert Spencer
, he was an auto-didact
). At 13 he became apprenticed to a hosier. He joined the Mechanics' Institute
(which had a library), studied in his spare time, and collected insects in Charnwood Forest
. In 1843 he had a short paper on beetles published in the Zoologist
Bates became friends with Wallace when the latter took a teaching post in the Leicester Collegiate School. Wallace was also a keen entomologist, and he had read the same kind of books as Bates had, and as Darwin, Huxley and no doubt many others had. Malthus on population, James Hutton and Lyell on geology, Darwin's Voyage of the Beagle, and above all, the anonymous Vestiges of the Natural History of Creation, which put evolution into everyday discussion amongst literate folk. They also read William H. Edwards on his Amazon expedition, and this started them thinking that a visit the region would be exciting, and might launch their careers.
The great adventure
In 1847 Wallace and Bates discussed the idea of an expedition to the Amazons, the plan being to defray expenses by sending specimens back to London where an agent would sell them for a commission, and for the travellors to "gather facts towards solving the problem of the origin of species
", as Wallace put it in a letter to Bates. The two friends, who were both by now experienced amateur entomologists, met in London to prepare themselves by viewing South American plants and animals at the main collections. Also they collected 'wants lists' of the desires of museums and collectors. Letters survive in the Kew library of letters from the pair asking what plants the Director (then William Jackson Hooker
) would like them to find. Never has the old adage of a prepared mind been more apposite.
Bates and Wallace sailed from Liverpool in April 1848, arriving in Pará (now Belém) at the end of May. For the first year they settled in a villa near the city, collecting birds and insects. After that they agreed to collect independently, Bates travelling to Cametá on the Tocantins River. He then moved up the Amazon, to Óbidos, Manaus and finally Tefé, which was his headquarters for four and a half years. His health eventually deteriorated and he returned to England, sending his collection by three different ships to avoid the same fate as Wallace. He spent the next three years writing his account of the trip, The Naturalist on the River Amazons, widely regarded as one of the finest reports of natural history travels.
Home at last
In 1861 he married Sarah Ann Mason. From 1864 onwards, he worked as Assistant Secretary of the Royal Geographical Society
(effectively, he was the Secretary, since the senior post was occupied by a noble figurehead). He sold his personal Lepidoptera
collection to Godman
and began to work mostly on beetles (cerambycids
, and cicindelids
). From 1868-9 and 1878 he was President of the Entomological Society of London. In 1871 he was elected a Fellow of the Linnaean Society
, and in 1881 he was elected a Fellow of the Royal Society
He died of bronchitis in 1892 (in modern terms, that may mean emphysema). A large part of his collections are in the Natural History Museum (see The Field, London, February 20, 1892). Specimens he collected went to the Natural History Museum [then called the BM(NH)] and to private collectors; yet Bates still retained a huge reference collection and was often consulted on difficult identifications. This, and the disposal of the collection after his death, are mentioned in Edward Clodd's Memories.
Henry Bates was one of a group of outstanding naturalist-explorers who were supporters of the theory of evolution
by natural selection
and Alfred Russel Wallace
1858). Other members of this group included J.D. Hooker
, Fritz Müller
, Richard Spruce
and Thomas Henry Huxley
Bates' work on Amazonian butterflies led him to develop the first scientific account of mimicry, especially the kind of mimicry which bears his name: Batesian mimicry. This is the mimicry by a palatable species of an unpalatable or noxious species. A common example seen in temperate gardens is the hover-fly, many of which – though bearing no sting – mimic the warning colouration of hymenoptera (wasps and bees). Such mimicry does not need to be perfect to improve the survival of the palatable species.
Bates noted of the Heliconids (long-wings) that they were forest-dwellers who were:
- 1. abundant 2. conspicuous and slow-flying. 3. gregarious; and also 4. the adults frequented flowers. 5. the larvae fed together.
And yet, said Bates "I never saw the flocks of slow-flying Heliconidae in the woods persecuted by birds or dragonflies... nor when at rest did they appear to be molested by lizards, or predacious flies of the family Asilidae [robber-flies] which were very often seen pouncing on butterflies of other families... In contrast, the Pieridae (sulfur butterflies), to which Leptalis belongs [now called Dismorphia] are much persecuted."
Bates observed that a large number of the Heliconid species are accompanied in the districts they inhabit by other species (Pierids), which counterfeit them, and often cannot be distinguished from them in flight. They fly in the same parts of the forest as the model (Heliconid) and often in company with them. Local races of the model are accompanied by corresponding races or species of the mimic. So a scarce, edible species assumes the appearance of an abundant robust, noxious species. Predators learn to avoid the noxious species, and a degree of protection covers the edible species, no doubt proportional to its degree of likeness to the model. All aspects of this situation can be, and have been, the subject of research. Thus began a field of research which is still quite active today.
Bates, Wallace and Müller believed that Batesian and Müllerian mimicry provided evidence for the action of natural selection, a view which is now standard amongst biologists. Field and experimental work on these ideas continues to this day; the topic connects strongly to speciation, genetics and development.
Note on taxonomy
Bate's original work was done on a group of conspicuous butterflies which he knew as the Heliconidae
. He divided this assemblage into two groups, the Danaoids, having affinities with the great family Danaidae
; and Acraeoids related to the Acraeinae
. The former are now known as Danainae
, the milkweed butterflies, main genus Danaus
. The latter are now known as Heliconiinae
, the long-wings, main genus Heliconius
. Both are subfamilies in the Nymphalidae
, and both groups tend to feed on poisonous plants. The milkweed plant supplies poisonous glycosides which render both caterpillar and imago Danaids noxious, and the Heliconid caterpillars feed on poisonous Passiflora
- Bates H.W. 1843. Notes on Coleopterous insects frequenting damp places. The Zoologist 1, 114-5.
- Bates H.W. 1863. The naturalist on the river Amazons. 2 vols, Murray, London.
- Bates H.W. 1864. The naturalist on the river Amazons. 2nd ed as one vol, Murray, London. [this is an abridged edition with much of the natural history cut out; and it is this truncated edition which is usually reprinted. Advice: use the 1863 or 1892 editions for professional purposes]
- Bates H.W. 1892. The naturalist on the river Amazons, with a memoir of the author by Edward Clodd. [this edition, published after Bates' death, is valuable for two reasons: it is the only time since 1863 that Murray published the full text, and it includes a good short biography by Clodd]
- Bates H.W. 1862. Contributions to an insect fauna of the Amazon Valley. Lepidoptera: Heliconidae. Transactions of the Entomological Society 23, 3, 495-566.
- Bates H.W. 1878. Central America, the West Indies and South America, with ethnological notes by A.H. Keane. Stanford, London; second and revised edition 1882. [based on Von Hellwald's Die Erde und ihre Volker; the natural history and geographical relations of fauna and flora are wholly written by Bates; the other aspects he extensively revised and updated]
- Bates H.W. 1881-4. Biologia Centrali-Americana Insecta. Coleoptera. Volume I, Part 1.
- Bates H.W. 1886-90. Insecta. Coleoptera. Pectinicornia and Lamellicornia. Volume II, Part 2.
- Bates H.W. and D. Sharp. 1879-86. Insecta. Coleoptera. Phytophaga (part). Volume V.
- Bedall B.G. (ed) 1969. Wallace and Bates in the tropics: an introduction to the theory of natural selection. Macmillan, London. [includes excerpts from Bates' River Amazons]
- Clodd, Edward 1892. Memoir [of Henry Walter Bates] 70 pages plus coloured plate 'illustrations of mimicry between butterflies', xvii-lxxxvii in Bates 1892.
- Edwards W.H. Voyage up the river Amazons, including a residence at Pará. London 1847. [the book that sparked Wallace and Bates]
- Moon H.P. 1976. Henry Walter Bates FRS 1825-1892: explorer, scientist and darwinian. Leicestershire Museums, Leicester. [this booklet of about 100 pages by an emeritus professor of zoology can be strongly recommended]
- Woodcock G 1969. Henry Walter Bates, naturalist of the Amazons. Faber & Faber, London. [this, the only book-length biography, is by an author who was not a biologist. It gives a weak account of Bates' work on mimicry, says nothing about Müller, and remarks about Wallace are undistinguished. It is good on Bates' early life and his marriage, and on the travel aspects of the Amazon. The author dismisses Bates' later life too abruptly]
- Blaisdell, M. (1982). "Natural theology and nature's disguises". Journal of the History of Biology. 15: 163–189.