Primates (2006) 47: 397–400
DOI 10.1007/s10329-006-0194-8
SH O RT CO MM U N IC A T IO N
Ruth Thomsen Æ Christian C. Voigt
Non-invasive blood sampling from primates using laboratory-bred
blood-sucking bugs (Dipetalogaster maximus ; Reduviidae,
Heteroptera)
Received: 22 July 2005 / Accepted: 23 March 2006 / Published online: 2 June 2006
Japan Monkey Centre and Springer-Verlag 2006
Abstract Primates are easily stressed by the conventional
veterinary blood sampling routine and consequently,
measured blood parameters may be biased. In this study,
we tested blood-sucking bugs (Dipetalogaster maximus)
on one lemur and two ape species (Microcebus murinus,
Pongo abelii, Pan paniscus) as an alternative, non-invasive technique for bleeding primates. Within time periods of between 6 and 62 min we obtained blood volumes
of 0.01–2.4 ml in 11 out of 12 trials from all three species. Therefore, we conclude that these bugs represent a
new, gentle and effective tool for bleeding captive primates without stress.
Keywords Blood sampling Æ Bug Æ Dipetalogaster
maximus Æ New technique Æ Stress-free
Introduction
Primates are frequently bled for research purposes.
More than 41,000 animals were reported to be examined
in all of the scientific investigations published in 2001
(Carlsson et al. 2004). During conventional blood sampling the target animal is captured, restrained and
anaesthetised. Both the stress induced by handling and
the anaesthesia may alter blood chemistry and the haemogram (Loomis et al. 1980; Wall et al. 1985). Furthermore, the use of conventional needles can lead to
imprecise puncturing of the blood vessel in the case of
species with diminutive veins, necessitating repeated attempts which may lead to haematomas or scars. Eventually, sequential bleeding of the same individual
becomes impossible. In short, the use of needles for
bleeding primates provokes stressful situations, one side
effect of which may be that stress-sensitive blood
R. Thomsen (&) Æ C. C. Voigt
Institute of Zoo and Wildlife Research,
Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
E-mail: thomsen@izw-berlin.de
Tel.: +49-30-5168701
parameters are biased (Capitanio et al. 1996; Reinhardt
and Reinhardt 2000).
An alternative blood sampling method is the application of blood-sucking bugs (Reduviidae, Heteroptera).
Blood-sucking bugs were used for the first time about
20 years ago to bleed bats (von Helversen et al. 1986).
These bugs (Dipetalogaster maximus) have subsequently
been applied to a variety of animal species other than
primates (R. Thomsen and C.C. Voigt, own data). When
possible effects of the bug’s haemolymph or saliva on the
blood sample were studied, it was shown that the sample
remains unchanged if it is redrawn from the bug’s crop
within approximately 30 min after the bug has finished
its blood meal. The blood then can be used for a variety
of analysis, including lymphocyte cultures (Volleth
1985), doubly-labelled water experiments (Voigt et al.
2003), antibodies (Voigt et al. 2006), determining the
concentration of steroid hormones (Voigt et al. 2004)
and haematology (R. Thomsen and C.C. Voigt, in
preparation).
The aim of this study was to test the use of D. maximus as a new and stress-free bleeding technique in three
threatened primate species (Microcebus murinus, Pongo
abelii, Pan paniscus).
Methods
Grey mouse lemurs weigh between 60 and 130 g and
possess diminutive blood vessels. From a study colony at
the University of Veterinary Medicine in Hannover, we
chose three adult males, each kept solitarily in a large
hanging cage with a small sleeping box (25·7.5·7.5). The
conventional method of bleeding grey mouse lemurs involves restraining the lemur in one hand and venipuncturing the ear vein or the saphenous vein (vena auricularis,
v. saphena magna). Sumatran orang-utans and bonobos
weigh between 40 and 100 kg. Both ape species are housed
at the Frankfurt Zoo. We chose an adult female orangutan and two bonobos, an adult male and an adult female.
Both females carried infants younger than 2 years of age.
398
The apes at Frankfurt are trained once daily with the
clicker-training method to come and sit close to the grid of
their home cages. This allows touching and grooming
from trained persons. In both species, conventional blood
sampling from the vein of the forearm (v. mediana antebrachii) usually involves an anaesthesia.
Dipetalogaster maximus (Reduviidae, Heteroptera)
develops in five larval stages (L1–5) until the imago (I)
hatches. Since each stage has a characteristic size (e.g.
L1 = 0.4 cm, Imago = 4 cm), the quantity of blood
required can be defined precisely from 0.1 to 4.0 ml (for
details, see Voigt et al. 2004). After the bug has recognised the victim, it punctures the skin with its proboscis,
which is 32-fold smaller in diameter than a common 26gauge needle, and then starts to suck blood. Immediately
after the initial sting, the bug releases pain-reducing
substances so that the host does not notice the parasite
(von Helversen et al. 1986).
All bugs used in this study were derived from our
laboratory-bred colony. Each bug routinely is used only
once (like needles are used only once as well) to avoid the
transmission of diseases from one animal to another. To
avoid contamination by bug haemolymph, we allowed
8 weeks to pass after the last blood meal for complete
digestion (Lehane 2005) and used exclusively ‘‘empty’’
bugs with a paper-thin abdomen. If the bug is not disturbed, the duration of blood-sucking lasts about
6–20 min until it has filled its crop completely (independently of its age). It then releases itself from the animal.
The sucking process can be interrupted easily at any time
by picking up the bug from the host with tweezers. To
collect the blood from the bug, its abdomen is punctured
with a needle. Since the bug releases heparinising substances into the ingested blood, any further preparation
of the blood is unnecessary (Voigt et al. 2003).
Applications for the bug must be developed depending on species and on cage type. Since all three species of
primates chosen for the present investigation are known
to feed on insects, efforts were made to protect the
sucking bug from being eaten. For the mouse lemurs, we
altered the sleeping box by substituting the solid wooden
bottom with a wire mesh (2·2 mm). Two hours before
the end of the daily sleeping phase, we attached a little
box with a starving bug (size L2, sucks a maximum of
0.3 ml) to the wire mesh side of the sleeping box (Fig. 1).
For bleeding the great apes, we used a non-transparent tube (12·2.5 cm) into which we hid a single bug
(L5, sucks a maximum of 1.5 ml, or Imago, sucks a
maximum of 4 ml). The front end of the tube was closed
with a gauze (1·1 mm) which prevented the bug from
moving directly on the skin while allowing it to pierce
the skin of the primate with its proboscis (Fig. 2).
Results
In the lemurs, the prepared sleeping box was attached to
the home cage. We then waited 20 min before checking
the bug for the size of its abdomen. The bug successfully
Fig. 1 Application-device for non-invasive blood sampling from
captive grey mouse lemurs (Microcebus murinus) using bloodsucking bugs (Dipetalogaster maximus, L2). The bug is hidden in a
flat box under the common sleeping box of the lemur, with the
latter attached to the outer side of the home cage. The wooden
bottom of the sleeping box was removed and replaced with a wire
mesh (2·2 mm) through which the bug can extend its proboscis.
When the bug’s abdomen is filled with blood, the box containing
the bug can be detached by spring catches without disturbing the
sleeping lemur
sucked blood from the focus animal in all trials (100%).
In bonobos and orang-utans, the use of an empty tube
was first incorporated into the training sessions for
10 days. As soon as the apes lost interest in the tube, we
transferred the bug into it and held it against the skin of
the apes for a period of between 6 and 62 min (including
some short interruptions). In seven of the eight trials
(87.5%) the bug successfully sucked blood (Table 1).
Discussion
In this study, the exemplary use of D. maximus for
stress-free bleeding of non-human primates turned out
to be appropriate in all six of the individuals tested (two
females and four males of three different species). The
species-specific application-devices that we developed
were assessed to be appropriate since the focus animals
never detected the bug. In mouse lemurs and bonobos,
our application-devices were successful in all trials and
in all individuals; in the female orang-utan, we succeeded in two out of three trials. During the failed trial
the female moved frequently back and forth to the grid
so that in the end, the bug’s proboscis twisted. It should
be noted that in both great ape species the females carried weaned infants during the blood sampling with the
bug – a scenario in which the use of a needle would have
been almost impossible. The success rate with the bug
was notably high since we obtained blood in 11 of the 12
399
Fig. 2 Application-device for bonobos (Pan paniscus) and orangutans (Pongo abelii). The bug (D. maximus, L5 or Imago) is hidden
inside the tube and allowed to sting through the gauze (1·1 mm).
Before applying the tube to the great apes it is covered with a black
tape to prevent the apes from detecting the hidden bug
trials (91.7%). To date there are no published data on
the success rate for bleeding primates with conventional
methods; however, based on unofficial information it
would appear that about every second trial (50%) fails
when needles are used. Thus, the bug method clearly is
not only more gentle, but also more efficient than a
needle.
Exact blood volumes can be determined by using the
adequate bug size (Voigt et al. 2004). Depending on the
different body masses of the focus species, we used bugs
of various larval stages to avoid collecting too much
blood, which could lead to drastic loss of blood volumes,
especially in small-sized primates. Since the blood volumes collected ranged between 0.01 and 0.2 ml (mouse
Table 1 Success rates of the use of laboratory-bred blood-sucking
bugs (Dipetalogaster maximus) for bleeding captive primates
Trials (n)
Success
Bug size
Time (min)
Blood volume (ml)
Microcebus
murinus
(n=3)
Pan
paniscus
(n=2)
Pongo
abelii
(n=1)
4
4/4 (100%)
L2
8–20
0.01–0.2
5
5/5 (100%)
L5 and Imago
6–62
0.1–2.4
3
2/3 (66.7%)
L5 and Imago
8–33
0.3 and 0.5
lemurs) up to 2.4 ml (bonobos), we never exceeded
commonly accepted recommendations for blood sample
volumes (<1% of body mass) when using the bug.
The period during which the bug was hidden inside
the application-device (flat box or non-transparent tube)
ranged between 6 and 62 min. Among the great apes, it
was more difficult to attach the tube to orang-utans than
to bonobos, since the orang-utans were more interested
in any kind of tools and playthings than the bonobos,
thus prolonging the time period for blood sampling.
Orang-utans tried to enter the tube with sticks or snitch
it, whereas the bonobos remained uninterested. Such
information, although currently anecdotal, might be
important for the development of an adequate application-device for bleeding chimpanzees (Pan troglodytes)
with the bug method, since chimpanzees are well known
to use a variety of tools for feeding on insects. The tubeapplication should fit very well in those species that are
not interested in playthings or insects and in those laboratories where primates are trained to present a limb
(Reichard and Laule 1993).
The application which we developed for mouse
lemurs worked perfectly in 100% of the trials. Thus, we
believe that this prototype should be applicable to other
small-sized primates held under similar conditions (e.g.
Callithrix or Galago spp.). However, even if the sleepingbox-application can not be used due to specific housing
conditions, the use of D. maximus for bleeding small
primates by holding them in one hand so that the bug
can be applied directly onto an adequate vein is still
more gentle than the use of needles since injuries are
avoided. Furthermore, in no case did any of the focus
animals develop visible signs of stress or an allergy or
other illnesses after the bug was used for blood sampling.
In summary, although the development of adequate
application-devices still requires skill, experience and
time, the use of laboratory-bred blood-sucking bugs
represents a new, gentle, effective and stress-less tool for
bleeding captive primates.
Acknowledgements Our thanks are extended to Dr. Ute Radespiel
and Prof. Dr. Elke Zimmermann for providing Ruth Thomsen
access to their lemur colony in Hannover. Special thanks go to the
Zoo Frankfurt and to the caretaker Carsten Knott who trained
Ruth Thomsen on how to cooperate with bonobos and orangutans. We also would like to thank Prof. Dr. Guenther Schaub for
providing his knowledge on the bug’s biochemistry and Prof. Dr.
Kiyoaki Matsubayashi for his helpful information on conventional
bleeding methods in primates. Ruth Thomsen thanks the ‘‘Berliner
Programm zur Förderung der Chancengleichheit für Frauen in
Forschung und Lehre, –16/04’’ for a grant to perform this study.
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