Ulisse Aldrovandi: De animalibus insectis libri VII (1623)

….. more complex than a star..and.. a far greater challenge to understand.[1]

Only four volumes of Aldrovandi’s huge work on the natural world were published during his lifetime. The first three were books on birds, the subject of an earlier blog[2], and the fourth was a book on insects, “De animalibus insectis libri VII” (1602). Worcester Cathedral Library has a copy of the edition published in 1623.

Title page of ‘De animalibus insectis libri VII’, Image copyright the Dean and Chapter of Worcester Cathedral (UK)

The Renaissance was a time of great interest in the natural world, but whilst mammals, birds and plants were popular topics for scholars, insects were rather neglected.  Sometimes artists included insects in trompe l’oeil and memento mori paintings to demonstrate their skill or as symbols, (flies meant evil and death, butterflies represented transformation and Christian resurrection and ants or bees symbolised industry and hard work). The insects themselves were not considered worth painting for their own sake, except for Albrecht Dürer’s beautiful watercolour of a stag beetle, of course!

Ulisse Aldrovandi’s was the first book to be published on insects and other small, insect-like invertebrates and he recognised the problems they presented. Small and difficult to see, insects are present in such abundance and variety as to be disheartening to the scholar trying to describe them or working out their life cycles. Aldrovandi was working a few decades before the invention of the microscope transformed the study of small creatures enabling pioneers of microscopy such as Robert Hooke and Anthony van Leuwenhoek to publish accurate drawings of tiny insect structures.

Beetles from ‘De animalibus insectis libri VII’, Image copyright the Dean and Chapter of Worcester Cathedral (UK)

Despite these difficulties, Aldrovandi set himself the goal of “finding, examining, and describing” as many “insects” as he could. Accompanied by a secretary and an artist, he scoured the environs of Bologna, interrogating peasants and asking them to collect specimens so that, “I was able to assemble a diverse collection (variam supellectilem) of insects” and of course, a huge collection of images of insects. These images were preserved for many years in Bologna and consulted by scientists from all over Europe. In 1664 English scholars John Ray and Francis Willoughby spent time studying the collection[3].

The great variety of insects Aldrovandi collected presented yet another problem. As always, he first looked to the classical authors for guidance, but “although there are many kinds of butterflies, I have found none described by the ancients.”

Butterflies and moths from ‘De animalibus insectis libri VII’, Image copyright the Dean and Chapter of Worcester Cathedral (UK)

To remedy this lack, Aldrovandi used words and pictures. He commissioned talented artists to paint the accurate watercolour images in his museum. In his books, descriptions of butterflies and moths include full-page woodcuts, each containing several different species accompanied by morphological descriptions and notes on their breeding or behaviour.

Aldrovandi developed a classification of the insect world, dividing insects first into “terrestrial or aquatic” then according to “has feet or no feet” followed by “has wings or no wings”, but this system led to some anomalies. For example, Aldrovandi classified caterpillars into the group with worms rather than flying insects.

It was Englishman Francis Willoughby, who had seen the collection in Bologna, that came up with the idea of classifying insects according to how they changed during their lifetime, their “metamorphosis”[3]. In his system, caterpillars and butterflies are in the same group, as are honeybee larvae and the adult bees.

Bees and wasps from ‘De animalibus insectis libri VII’, Image copyright the Dean and Chapter of Worcester Cathedral (UK)

Honeybees were important to Aldrovandi and he devotes the first chapter of his book to them and their cousins the wasps. He recognises the importance of bees and of honey as a food and medicine since ancient times, describing the ancient Assyrian custom of preserving dead bodies in honey. But the  bees’ reproduction was still obscured by the Aristotelian theory that all larvae, “worms,” were imperfect animals that generated spontaneously. At their death, they formed an egg – the pupa – that then gave birth to a completely new creature, the adult insect.

Aldrovandi’s section on butterflies and moths has similar difficulties although the engravings clearly show adult insects emerging from their pupae.

Caterpillars and chrysalis, one showing an emerging adult insect, from ‘De animalibus insectis libri VII’, Image copyright the Dean and Chapter of Worcester Cathedral (UK)

The books include chapters on flies, grasshoppers, locusts and beetles but also spiders, scorpions, worms, slugs and starfish, which are no longer considered to be insects.

Grasshoppers, crickets and praying mantids from ‘De animalibus insectis libri VII’, Image copyright the Dean and Chapter of Worcester Cathedral (U

It may seem that Aldrovandi just failed to see the obvious in his conclusions about insect reproduction, but that is rather harsh.  He was the first scientist to describe insect parasitoids. Parasitoids are insects which lay their eggs inside another species and whose larvae live in the host until it emerges, “Alien”-like,  as an adult, usually killing its host. This widespread (and grisly) phenomenon no doubt contributed to the confusion surrounding insect reproduction.

For many insects, Aldrovandi’s descriptions and illustrations are the oldest in the entomological literature and a large number of species can be identified today from his illustrations. Some specimens however, such as the “owl fly” shown, continue to be a puzzle.

The “owl fly” from ‘De animalibus insectis libri VII’, Image copyright the Dean and Chapter of Worcester Cathedral (UK)

In 2008, Rinaldo Nicoli Aldini summed up Aldrovandi’s De animalibus insectis in a paper in the journal ‘Bulletin of Insectology’

“If we consider the way Aldrovandi treated…insects …… … his interest in biodiversity and his systematic aim to classify …. his exploitation of the iconography, his consideration of practical topics, and his very wide knowledge of past literary and scientific sources……. make his work a mine of information for the history of entomology.”

One suspects that Aldrovandi would be delighted!

Diana Westmoreland


Rinaldo Nicoli Aldini (2005) Ulisse Aldrovandi and Antonio Vallisneri: the Italian contribution to knowledge of Neuropterous Insects between the 16th and the early 18th centuries Proceedings of the IX International Symposium on Neuropterology Ann Mus civ. St. nat. Ferrara (2007)

Cassidy Phillips (2019) Fantastic beasts and unnatural history https://wellcomecollection.org/articles/XIfIrRAAAKbQ-_v9

Brian W. Ogilvie (2005) Description and Persuasion in Seventeenth-century Entomological Illustrations

The Works of Conrad Gessner and Ulisse Aldrovandi https://books.openedition.org/mnhn/2815?lang=en

Janice Neri (2011)  The Insect and the Image. Visualizing Nature in Early Modern Europe, 1500-1700 Minneapolis and London: University of Minnesota Press,

Rinaldo Nicoli Aldini (2008)  Apis amphibia, Cicada, Cimex, Cimices sylvestres, Tipulae… The insects now known as Hemiptera, in Ulisse Aldrovandi’s De Animalibus Insectis (1602) Bulletin of Insectology 61 (1): 103105

Rinaldo Nicoli Aldini  (2019) What is the supposed “owl fly” illustrated in Aldrovandi’s De animalibus insectis (1602) https://www.researchgate.net/publication/344172897

[1] An insect is more complex than a star..and is a far greater challenge to understand.                                              

[2] https://worcestercathedrallibrary.wordpress.com/2021/10/13/birds-bats-and-monsters-ornithologiae-de-avibus-historiae-by-ulysse-aldrovandi/

[3] https://worcestercathedrallibrary.wordpress.com/?s=mr+willughby+and+mr+ray


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