The approach to field entomology that I have chosen to pursue involves sampling using just my eyes and ears and taking nothing more than notes and photos, while endeavouring to minimize any negative impact that I might have on habitats or organisms through my presence.... Killing to conserve did not seem like it was even close to being the right thing to do.
And he that breaks a thing to find out what it is has left the
path of wisdom.
~ Gandalf in "The Fellowship of the Ring"
Here, I make a case for an approach to the study of insects and
other arthropods that I will call compassionate entomology. My use
of the first term in this construction follows its application in
compassionate conservation, where it signifies the explicit
consideration of the welfare and intrinsic value of individual
organisms (especially vertebrates) within the praxis of conservation
biology. With the second term in the construction, I refer here, and
elsewhere in this article, to the study of not just insects—as in
the strict sense of entomology—but other arthropods too, such as
spiders, centipedes, and springtails. Compassionate entomology,
then, is a way of studying insects and other arthropods that upholds
the intrinsic value and welfare interests of the individual focal
organisms.
My motivation for writing this piece is to offer a counter to the
prevailing viewpoint among entomologists, which is that the goal of
attaining more knowledge and greater understanding generally trumps
concerns for the survival and well-being of individual organisms.
Through such an outlook, killing a bumblebee is justified if it
allows her to be identified to species level. Similarly, ending the
life of a millipede is a desirable course of action if the purpose
is to obtain a voucher specimen (physical evidence for a record of
the species being present in a certain place on a particular date).
And terminating a beetle is a good thing to do if it allows a
naturalist to extend their reference collection.
This approach to entomology is one that I myself adopted—albeit
tentatively and for only a short while—when I began to study
arthropods with a degree of seriousness twelve years ago. I had
sought advice from several respected entomologists in my local area,
and pursuing such a path was something that they unanimously urged.
It must be acknowledged that there was a strong rationale supporting
what they had to say. For one thing, many arthropods cannot be
reliably separated from close relatives without being killed (often,
to allow their genitalia to be dissected), and the knowledge that
can be obtained in this way helps conservationists to build up more
complete local species inventories and to monitor temporal trends
for a broader diversity of organisms. Correspondingly, reference
collections are a valuable tool for guiding species identifications,
while voucher specimens allow old records to be re-examined
according to new information.
Furthermore, the respected figures with whom I spoke were people
generously applying their considerable talents to support the
understanding and conservation of arthropods. And the practice of
killing insects was something that, by and large, they defended with
passion. Their zealousness was evident, too, in the literature. In a
2008 book on the study of dragonflies, for instance, Philip Corbet
and Stephen Brooks wrote: “The conduct of odonatology can be
severely compromised if non-odonatologists try to prevent
odonatologists from collecting specimens… We cannot emphasize
strongly enough that such behaviour constitutes a severe threat to
the future viability of odonatology – as a science – and so should
be promptly and unequivocally denounced.”
I want to be clear, therefore, about the following: Balancing the
ethical considerations in this area can be far from straightforward;
and the challenge to the prevailing viewpoint that I present in this
article is not intended as a slight to the character of
well-intentioned researchers.
In the case of my own reference collection, I had pinned no more
than a dozen insects—a few of whom had died of natural courses, with
the others being terminated by exposure to gaseous ethyl
acetate—when I chose to turn away from the accepted wisdom. For me,
killing to conserve did not seem like it was even close to being the
right thing to do.
In parallel, I began to develop a dislike for the techniques
typically employed to find arthropods in the field, which included
sweeping vegetation with a metal-framed net and beating the branches
of trees to dislodge organisms onto a sheet. The former
inadvertently causes damage to the antennae and limbs of at least
some of the arthropods caught (as well as shearing off the heads of
weaker-stemmed flowering plants). The latter, meanwhile, can remove
hundreds of organisms from a tree with a single blow, many of whom
will be wingless in form. It follows, with this second method, that
when an entomologist opts against diligently returning each of the
flightless creatures to the beaten branch of their host-plant, and
instead discards them on the ground beneath the tree (as is the
common practice), that person is at best causing significant
interference in the lives of the affected organisms and at worst
consigning them to death.
Plant bugs, such as the grass-feeding Megaloceroea recticornis, are
one group of arthropods with particularly fragile limbs
Other sampling methods, such as pitfall and flight-interception
trapping, never appealed to me (with or without the use of a liquid
to swiftly kill all of the caught organisms). Like most
entomologists, I restrict my efforts in identifying arthropods to a
limited number of groups within the phylum, and any trapped beings
outside my focus would thus be bycatch, to employ the standard
lingo. If the ethics of harming or killing an individual from a
target species are problematic, then those for doing the same to
non-target organisms—collateral victims, as they might be termed—are
only more so.
Instead, the approach to field entomology that I have chosen to
pursue involves sampling using just my eyes and ears and taking
nothing more than notes and photos, while endeavouring to minimize
any negative impact that I might have on habitats or organisms
through my presence. And where I have had the opportunity to lead
courses on field entomology, including for the Field Studies
Council, I have given prominent coverage to arthropod welfare. This
has involved, for instance, offering detailed practical advice on
ways to avoid or minimize the negative impacts on individual
organisms caused by entomological activities.
With respect to my chosen approach, the new discoveries being made
on the extent of sentience in arthropods have only reinforced my
resolve. Nevertheless, despite calls—such as that made in a 2019
paper by Bob Fischer and Brendon Larson—for practitioners to revisit
their ethical codes in light of consciousness-related discoveries,
the harming and killing of arthropods seems to remain a sacred cow
for many leading entomologists.
The reluctance to change may result in part from the idea that to do
so would diminish the discipline’s scientific rigour—a view that has
been expressed, to give one example, in the aforementioned work on
dragonflies. Relatedly, in a 2023 book on shieldbugs, Richard Jones
opines that “you do not need to kill insects to study entomology,
but if you do, then your contribution will be more profound and
longer lasting.” I dispute such assertions by drawing on healthcare
for an analogy. Here, ethical considerations restrict the hypotheses
that can be tested and the trial designs that can be employed
(planned asbestos exposure to yield new insights on asbestosis, for
instance, would not be acceptable), but this does not lead medical
scientists to say that their field has a reduced rigour or that its
discoveries have a lesser profundity.
Of course, backing away from causing death or other significant harm
to arthropods, as guided by the beacon of compassionate entomology,
means accepting a reduction to the maximum extent of what we can
hope to know about them, in a scientific sense. In the next section,
I reflect on the possible ramifications for conservation efforts of
reducing the sphere of knowledge in this way. Following on from
that, I offer a few supplementary comments on research entomology.
I will note first, though, that since a call for restricting our
scientific ambition may be seen as heresy by some members of the
field, it is perhaps fortunate that several years ago I ceased to
pay the annual dues for—and thus surrendered—my awarded fellowships
of the Royal Entomological Society and the Linnean Society of
London.
Conservation and compassionate entomology
If the purpose of seeking a new piece of entomological knowledge is
merely to increase human understanding, then I cannot see how the
harming or killing of the subjects of study can be considered
morally justifiable in any value system other than one strongly
skewed towards anthropocentrism. In contrast, where the rationale is
based on informing or supporting conservation activities, the
situation becomes more intricate. As described above, there are
implications to be considered for the assembly of reference
collections and retention of voucher specimens, the completeness of
local species inventories, and the breadth of organisms for whom we
can chart temporal trends. I shall examine each of these areas in
turn before offering a framework for arthropod conservation that is
not underpinned by the goal of identifying every organism to species
level.
Reference collections and voucher specimens
In compassionate entomology, the identification of individual
organisms is guided principally by consulting images and drawings,
and the assembly of reference collections becomes unnecessary. This
does not mean, though, that existing publicly accessible collections
lose their utility. They are still valuable as educational tools,
and they may also prove useful for helping identify arthropods who
have died without the agency of an entomologist.
A photo of mating cinnamon bugs that could be used to help with
identifying the species
In addition, compassionate entomology champions photographs over
voucher specimens as verifiable evidence, obviating the need to kill
the subjects of study. The higher the quality of the images
supporting each record—in terms of clarity and sharpness across a
breadth of body parts—the better they will serve their purpose. And
while even the best photographic rendering will not capture all
aspects of an organism’s anatomy, it has the advantages of being
easy to share, of allowing backups to be made, and of preserving
coloration and patterning that may fade in physical specimens.
Furthermore, the time saved in not having to obtain, prepare, and
store dead arthropods can be used to do more recording in the field.
These factors at least partially offset the information that is lost
through shifting away from the collection of physical evidence.
Crucially, such changes to the customs of entomology will not
undermine the robustness of the biological data that support
arthropod conservation efforts, because the process by which they
are collected and stored still honours scientific norms.
Completeness of local species inventories
In some groups of arthropods, such as butterflies, most or all
species can be identified in the field. Within others, th0ugh,
opting against killing means losing the ability to discriminate
between certain organisms and, in those cases, having to consider
biodiversity at the slightly less granular level of species
aggregates.
Orange-tips, like the vast majority of butterfly species, are
relatively easy to identify in the field with experience
Now, if conservation operated by tailoring management plans at
different sites to meet the precise needs of every declining or
threatened arthropod, then limiting our powers of discrimination in
this way might be detrimental. Only in a fairy tale, though, could
this work. The reality is different for several reasons: there are
too many kinds of organism for such an approach to be practicable;
we rarely know enough about the ecological nuances and local
population dynamics of individual species (especially
hard-to-identify ones) to be able to help them in this way; and
there will always be irresolvably conflicting requirements. What’s
more, all of the successful single-species conservation programmes
involving arthropods of which I am aware have focused on organisms
who could be identified while alive.
Breadth of organisms for charting temporal trends
Conservation, of course, is not only about on-the-ground
intervention (or non-intervention). At a higher level, there is a
need to shape broader policies that have a direct impact on
non-human life, such as national forestry guidance, and the process
of influencing such documents is aided by high-quality evidence on
temporal trends in biodiversity. Fortunately, foregoing the
theoretical ability to identify every species present in an area
does not have to mean lessening the weight of evidence that can be
gathered. Simply put, it is not necessary to chart the dynamics of
every single species of arthropod to make a strong case that these
organisms, on the whole, are in rapid decline. Instead, such
inferences can be made from a subset of organisms.
Furthermore, statistically speaking, the more observations that are
collected for any one species over a period of time, the stronger
the inferences that can be made about temporal trends for that
organism. Accordingly, species who are easier to identify lend
themselves to the generation of more compelling data. This
relationship is amplified by the greater engagement in citizen
science schemes that is possible when participants are not required
to kill arthropods. As compared with experienced entomologists,
there is generally much more compunction in members of the general
public to do this; and theirs is a voice that I think the scientific
community would do well to hear.
A compassionate framework for the conservation of arthropods
Following on from the points presented above, I believe that
arthropod conservation can operate effectively with the following
four-tiered approach (graded from the most general to the most
targeted efforts). The framework is compatible with compassionate
entomology because nothing within it requires killing arthropods or
causing them other significant harm.
Compassion in research entomology
Special mention must be made, before I close, of research
entomology, which has a history of extraordinarily destructive
experimentation. There are two publications illustrating this that
have stuck in my mind from when I was studying for a forestry
degree, but others could be cited with even higher levels of harm
and killing.
The first is a classic paper on island zoogeography by EO Wilson and
Daniel Simberloff, in which seven mangrove islets in the Florida
Keys, ranging in diameter from 11 to 25 metres, were covered in
tents and fumigated with methyl bromide in order to kill all of the
resident arthropods. The treatment applied was so potent that it not
only had its intended effect but also caused browning of the leaves
and shoots of the mangrove trees and some heavy oozing of sap.
Previously, the researchers had tried spraying the islets with
insecticide “until dripping,” but some arthropods who were sheltered
inside thin hollow twigs had survived the chemical onslaught, and so
a more comprehensively lethal method had been sought.
A partially opened fumigation tent over one of the islets in Wilson
and Simberloff’s study (top); and a completely opened one over
another islet (bottom; part of Figure 9 from the original
publication, adapted here for a non-commercial purpose under
presumed fair use)
The second publication is one by Martin Jukes and colleagues from
the early 2000s, which was funded by a government forestry agency.
In their study, 44 plots, each 100 metres square, across a dozen
forested sites in Britain were fogged with insecticide for up to 15
minutes using a small jet engine. Organisms knocked out of the trees
after chemical exposure—the “drop,” as the authors termed them en
masse—were caught by funnels that emptied into pots containing
methylated spirits. In all, the researchers were able to catalogue
11,074 dead beetles from their sampling. No mention is made of the
number of non-target arthropods collected or of the impact on
organisms who did not get caught (some will not have been dislodged
by the spraying within the two-hour collecting window, and others
will have missed the funnels, which covered only 0.25% of each
plot). The paper has, according to Google Scholar, gained an average
of two citations per year since its publication.
In a more recent paper—one by Hallmann and colleagues that was
picked up by the popular press—a 75-per-cent decline was reported
over a 27-year period in the biomass of flying insects within
protected areas in Germany. The data came from flight-interception
trapping that killed millions of individual insects. The resulting
publication is undoubtedly a helpful one in demonstrating how
serious the decline of insects has been in modern times, even within
protected areas. The finding, however, is not a controversial one,
as it substantiates what long-serving field entomologists already
know in less precise terms. And I cannot help think that evidence of
a sufficiently persuasive nature could have been gathered without
recourse to lethal sampling. More generally, the time has come, I
feel, for research entomology to step away from destructive methods.
Closing remark
I am not expecting, in having shared my thoughts here, that the
field will transform overnight. I do hope, however, for two more
realistic outcomes. The first is that any experienced practitioner
who is already uncomfortable with the accepted customs against which
I have argued might gain more courage to speak up about their
concerns and help lead the change. The second is that for budding
students of entomology who are worried about what a commitment to
the area might entail, it will be clear that a kinder and more
ecologically sound alternative is perfectly possible.
References
Corbet PS and Brooks SJ (2008) Dragonflies (New Naturalist Library).
Collins, London, UK.
Fischer B and Larson BM (2019) Collecting insects to conserve them:
a call for ethical caution. Insect Conservation and Diversity 12:
173–82.
Hallmann CA et al. (2017) More than 75 percent decline over 27 years
in total flying insect biomass in protected areas. PLoS ONE 12:
e0185809.
Jones R (2023) Shieldbugs (New Naturalist Library). Collins, London,
UK.
Jukes MR et al. (2002) The influence of stand structure and
composition on diversity of canopy Coleoptera in coniferous
plantations in Britain. Forest Ecology and Management 163: 27–41.
Wilson EO and Simberloff DS (1969) Experimental zoogeography of
islands: Defaunation and monitoring techniques. Ecology 50: 267–78.