The Cambridge natural history, Vol. 06 (of 10)

In Short

David Sharp’s The Cambridge Natural History, Vol. 06 (of 10) is an authoritative, sweeping survey of the major insect orders—including Hymenoptera, Coleoptera, Lepidoptera, Diptera, and Hemiptera. Blending anatomical rigour with field observations, Sharp walks readers through the life cycles, nesting behaviours, structural mechanics, and ecological adaptations of creatures ranging from subterranean ants and parasitic wasps to iridescent beetles and scale insects. Rather than relying on rigid taxonomy, the book brings natural history to life by highlighting the strange, automated intelligence driving insect instincts. It traces how physical adaptations meet the demands of survival across every continent. The volume has endured as a classic because of its balance between scientific thoroughness and readable, narrative prose. Sharp synthesises nineteenth-century field experiments with global naturalists' reports, creating a comprehensive window into the sheer diversity of the insect world that remains an indispensable foundational text for entomologists and naturalists alike.

The Story

The volume opens with the broad, complex realm of the Hymenoptera, focusing heavily on the social and solitary life cycles of bees, wasps, and ants. Sharp explores the intricacies of insect instinct, evaluating how species carry out elaborate building and provisioning rituals. In examining the solitary mason-bees (Chalicodoma), he recounts Jean-Henri Fabre’s famous experiments, which reveal the rigid, step-by-step nature of insect routine: a bee interrupted during its task will compulsively restart an entire sequence of actions rather than resume where it left off. From the solitary masons, the focus moves toward stingless social bees (Melipona and Trigona) in South America and Jamaica, detailing how they fortify their hives with walls of mud and clay, deploy single sentinels to guard narrow hive entrances, and store honey in large, pigeon-egg-sized clusters separate from their brood.

The study then transitions into the life cycle of social wasps, tracing the foundational work of a single queen-wasp in the spring. Building a handful of small, circular cells, she lays eggs and feeds the emerging larvae on chewed insect pulp—frequently targeting Diptera or honey-bees—until the first generation of worker females emerges to assume control of the colony. The narrative tracks the expansion of the nest through late summer, the creation of larger cells for males and perfect females, and the inevitable autumn collapse of the society, where enfeebled workers drag remaining larvae from their cells before dying off, leaving only young queens to hibernate through the winter. This sequence of solitary labor transitioning into social organization leads into the fossorial wasps (Sphex), which construct multi-chambered underground galleries. Sharp documents how these wasps paralyze field-crickets or locusts with pinpoint sting precision, dragging the motionless prey into burrows to feed the unborn larvae.

Moving deeper into the Hymenoptera, the text addresses the complex dynamics of ant colonies (Formica, Polyergus, and Anochetus). Sharp details the phenomenon of slave-making ants like Polyergus rufescens, which raid foreign nests for larvae and pupae. Once hatched, these captive workers perform all nest maintenance and feeding duties for their captors, whose mouthparts have become so specialized for battle that they are physically incapable of feeding themselves or their young. The survey continues through subterranean, predatory, and vaulting ant families, examining unique physical adaptations such as the spring-loaded mandibles of Anochetus that act as mechanical levers to propel the insect through the air.

Transitioning to Coleoptera (beetles), Sharp outlines the massive diversity of the order, beginning with the destructive life cycles of cockchafers (Melolontha vulgaris), whose subterranean larvae spend up to five years feeding on plant roots before undergoing a lengthy underground pupation. The text moves from aquatic beetles (Parnidae) that carry bubbles of air under water to eyeless cave-dwelling beetles (Leptoderini) and timber-inhabiting wood-borers. Particular attention is given to the snout-beetles (Rhynchophora), where the prolonged rostrum of the female serves as a specialized drill to construct deep egg-chambers in plant tissues.

The trajectory advances into Lepidoptera (butterflies and moths), examining the physical structures of wings, scales, and abdominal segments. Sharp discusses sexual dimorphism and mimicry, drawing on examples from the Amazon and the Malay Archipelago where female butterflies (Ornithoptera) differ radically from their brightly colored, emerald and gold male counterparts. He highlights larval defense mechanisms—such as caterpillars that mimic damaged oak leaves—and the mechanical strategies used by emerging pupae to saw through tough silk cocoons.

In Diptera (true flies), the work examines the radical metamorphosis that separates larval structures from adult forms, detailing blood-sucking sand-flies, aphid-devouring hover-fly larvae, and parasitic bat-flies (Nycteribiidae). Finally, the volume turns to Hemiptera (bugs), culminating in the long, subterranean life cycles of cicadas and scale insects (Coccidae). Sharp documents the deafening acoustic organs of male cicadas and the remarkable, multi-year developmental phases of scale insects, bringing the expansive survey to a close by detailing how tiny, sedentary parasites build protective waxy shields and alter their physical structures over years of growth.

How It Unfolds

The mechanics of insect routine The text introduces Hymenoptera by examining how solitary bees construct and provision their nests. Through controlled disruptions, experiments demonstrate that insect instincts function through a strict, consecutive sequence of automatic actions rather than flexible reasoning.

Fortresses of the stingless bees Moving to tropical stingless bees, the focus shifts to defensive architecture and colony preservation. Species in the Amazon and the West Indies use clay, wax, and specialized sentinel workers to guard hive entrances and shield honey stores from ants and monkeys.

Rise and fall of the wasp colony The social life cycle of wasps is charted from the lone queen's spring cell-building to the rapid expansion of worker generations. The narrative traces the colony's late-summer production of fertile queens and its abrupt autumn collapse, where starving workers purge the remaining brood.

Surgical precision of the burrowing wasps Fossorial wasps demonstrate specialized predatory habits by excavating complex underground galleries. They systematically sting and paralyze crickets or locusts, preserving live meat for their offspring without killing the prey.

Dependency and warfare among ant colonies The study explores complex ant behaviors, focusing on slave-making species whose specialized physical structures render them reliant on captive workers for daily feeding. Specialized mandibles used for jumping and defensive maneuvers are also examined.

Subterranean life and beetle metamorphosis Transitioning to Coleoptera, the text details the multi-year developmental cycles of root-feeding beetle larvae. It surveys aquatic, cave-dwelling, and timber-inhabiting species, showing how structural variations adapt beetles to extreme environments.

Elegance, dimorphism, and defense in butterflies In Lepidoptera, the focus shifts to wing structures, extreme differences between male and female colorations, and protective mimicry. Caterpillars employ physical camouflage resembling bitten leaves, while pupae use chitinous spines to break out of cocoons.

Radical transformations of the Diptera The work surveys true flies, analyzing how complete cellular breakdown during pupation bridges the gap between legless maggots and winged adults. Aquatic larvae, blood-sucking flies, and specialized bat parasites are systematically categorized.

Acoustics and life cycles of the Hemiptera The volume concludes with true bugs, highlighting the subterranean development and sound-producing organs of male cicadas. It details the unusual post-embryonic transformations of scale insects that spend years hidden beneath protective waxy shields.

The People

The Queen-Wasp Driven by an absolute imperative to found a new colony, the solitary queen-wasp begins her work in early spring by hand-crafting the initial cells of a nest. She acts as builder, hunter, and caregiver, capturing living insects and reducing them to pulp to feed her first brood. Once her infertile worker daughters emerge, her role transforms entirely; she retires to the interior of the nest, surrendered to continuous egg-laying while her offspring maintain the expanding society until autumn's fatal decline.

Fabre’s Mason-Bee (Chalicodoma) Operating as an industrious automated builder, the mason-bee seeks only to construct, provision, and seal individual stone cells for its offspring. It encounters insurmountable confusion when human intervention alters its environment, revealing the unyielding boundaries of its instincts. If interrupted midway through laying down provisions, it cannot adjust its logic; it instead repeats useless physical routines, demonstrating a mechanical obedience to sequential cycles.

The Slave-Making Ant (Polyergus rufescens) A fierce predator designed entirely for combat, Polyergus rufescens relies on organized raids against neighboring ant nests to capture larvae and pupae. Because its mouthparts have evolved into razor-sharp weapons incapable of delicate feeding tasks, it cannot nourish its own young or consume food without assistance. It becomes entirely dependent on its captured servitor ants, which manage the household, feed the host ants, and defend the shared nest.

The Male Cicada Existing primarily to sing and reproduce, the male cicada emerges from years of subterranean larval growth into a brief aerial life. Equipped with powerful, specialized muscular membranes on its abdomen, it produces shrill, resounding acoustic calls that can be heard across vast distances. Its brief adult phase stands in stark contrast to its quiet, years-long developmental period spent buried in the soil.

The Female Scale Insect (Coccid) Beginning life as an active, mobile larva, the female scale insect quickly selects a spot on a host plant, inserts her beak, and loses the ability to move. As her legs, antennae, and eyes atrophy, she becomes a sedentary, shield-like organism dedicated solely to absorbing sap and secreting protective waxy coverings. She lives out her life transformed into a living, stationary shell that houses her developing eggs.

In Its Own Voice

"If after the honey has been discharged, the bee be interfered with and gently removed to a slight distance with a straw, it returns to complete its task, but instead of going on with the actions at the point at which the interruption took place, it begins the series over again..."

Sharp notes this rigid, cyclic routine during Jean-Henri Fabre’s experiments with mason-bees restoring their stored provisions.

"In no case does the bee go back from the provisioning stage to the building stage until the cycle for one cell of building, provisioning, and egg-laying is completed: but when this is the case, the building of a fresh cell may be again undertaken."

This observation underlines the absolute structural necessity driving solitary insect behavior, where each phase must be finished in strict sequence.

"The fly bears no resemblance whatever to the larva, and is only obtained by the organic destruction of the latter, which occurs before the perfection of the sexual organs takes place, and yet the fly reproduces itself only secondarily, but primarily gives rise to the totally different larva."

Sharp reflects on the profound biological mystery of Dipteran metamorphosis, where adult flies pass down genetic blueprints for larval forms completely unlike themselves.

What It's Really About

Beneath its systematic classification of insect orders, the volume investigates the fundamental boundary between automatic instinct and flexible intelligence. Sharp uses empirical observations of insect habits to question how complex behavioral routines develop and persist. The text continually highlights how intricate architectural feats, surgical paralysis of prey, and colony management are carried out without conscious reflection or individual innovation.

Another major theme is the relentless efficiency of evolutionary adaptation. Sharp illustrates how every physical variation—from the drill-like rostrum of a snout-beetle to the sound-producing membranes of a cicada—serves an explicit survival requirement. The text systematically shows that strange forms are not mere aesthetic anomalies, but functional solutions to environmental challenges.

The book also grapples with the biological mysteries of inheritance and metamorphosis. By examining how a winged fly emerges from the complete tissue breakdown of a legless maggot, Sharp raises questions about how complex life cycles are encoded and transmitted across generations. The text emphasizes that individual survival is subordinate to the continuation of the species' developmental cycle.

Finally, the work explores the interconnectedness of natural ecosystems. By documenting parasitic relationships, slave-making behaviors, and predatory dynamics, Sharp presents the insect world as a tightly woven network where the specialized survival strategy of one organism directly depends on—and shapes—the life cycle of another.

Why Read It Today

The Cambridge Natural History, Vol. 06 remains a masterclass in direct, patient scientific observation. Modern readers accustomed to quick summaries will find deep satisfaction in Sharp’s rigorous, grounded prose. It offers an unhurried, detailed exploration of the physical mechanics and daily habits of creatures that are often overlooked, turning the micro-world of gardens, forests, and soil into a vivid arena of survival.

The book feels like a field notebook mixed with a formal lecture, where precise anatomical descriptions are paired with natural history anecdotes. Sharp avoids hyperbole, letting the unusual facts speak for themselves: beetles that carry air pockets under water, ants that function as specialized living levers, and moths that saw through their own cocoons. Reading the volume instills a renewed sense of wonder at the sheer diversity and mechanical complexity of small organisms.

Readers should be prepared for nineteenth-century scientific terminology and dense structural descriptions, particularly regarding wing venation, tarsal segments, and taxonomic controversies of the period. Sharp writes for an educated, attentive audience, and his prose demands deliberate reading. Furthermore, the taxonomy reflects the state of entomology in 1899, offering a historic window into how early naturalists organized and debated the relationships between insect families.

What stays with the reader is a permanent shift in perspective regarding the intelligence and structure of the natural world. Sharp reveals that the soil beneath our feet and the air around us are filled with complex, highly specialized routines running on unyielding evolutionary logic. It is a rewarding read for naturalists, historians of science, and anyone curious about the subtle, mechanical miracles of the insect world.