Angewandte
Chemie
DOI: 10.1002/anie.200906312
Pheromones (2)
Acylated Serine Derivatives: A Unique Class of Arthropod
Pheromones of the Australian Redback Spider, Latrodectus hasselti**
Elena Jerhot, Jeffrey A. Stoltz, Maydianne C. B. Andrade, and Stefan Schulz*
Spiders are of great ecological importance, as they are the
major predators of terrestrial insects. Many species use
chemical communication along with other cues during court-
ship, but these systems are not well investigated, especially
compared to other arthropods, such as insects or mites.
Spiders commonly make use of silk; mate attraction, initia-
tion of courtship, and other critical aspects of spider
reproduction are apparently triggered by pheromones on
the silk or the body of the female.[1,2] Most of the handful of
spider pheromones that have been identified are structurally
different from those known from insects. Herein, we report
the identification of the unusual methyl ester of N-3-
methylbutyryl-O-(S)-2-methylbutyryl-l-serine 3 as a female
sex pheromone of the Australian redback spider, Latrodectus
hasselti. This compound represents a new class of secondary
metabolites, N,O-diacylated serine derivatives.
Despite widespread reports of the importance of chemical
communication in spiders,[1] only five spider pheromones
have been identified to date. The estolide of two (R)-3-
hydroxybutyric acid units, (R,R)-3-(3-hydroxybutyryloxy)bu-
tyric acid, induces web reduction behavior in males of the
linyphiid Linyphia triangularis.[3] The S-enantiomer of asym-
metric dimethyl citrate releases courtship in males of the
American wandering spider, Cupiennius salei.[4] 8-Methyl-2-
nonanone, which is emitted by females, attracts males and
induces courtship response in the desert spider Agenelopsis
aperta.[5] A mixture of fatty acids has been reported to act as
courtship pheromone in the agenelid spider, Tegenaria
atrica,[6,7] whilst (E,E)-farnesyl acetate and hexadecyl acetate
were identified as pheromone of Pholcus beijingensis.[8]
Black widow spiders (Latrodectus, Theridiidae) are of
particular interest for humans because of their neurotoxic
venom[9] and the invasive nature of several species, which tend
to live in close association with humans. Behavioral inves-
tigations have shown that webs of female black widows
contain pheromones that attract males, trigger courtship, and
allow discrimination of female reproductive status, popula-
tion of origin, and species.[10–14] For example, males of L.
hesperus and L. hasselti are attracted to webs of females by
volatile cues.[11,12]
L. hasselti males display courtship on webs of adult
unmated females, whilst webs rebuilt by females after mating
and those of juveniles or males cause no response.[14] Experi-
ments have shown that a pheromone is deposited on the web
by unmated adult females. This compound can be extracted
with methanol, and it elicited searching and courtship
behavior in males when applied to filter paper.[14] Therefore
we became interested in the identification of this courtship-
inducing pheromone.
Silk from unmated (active) and mated (inactive) females
were collected during a period of several weeks and extracted
with methanol. Both extracts were then analyzed to identify
compounds specific for active silk; that is, putative phero-
mone candidates. After a derivatization step, the extracts
were analyzed by GC-MS with N-methyl-N-(trimethylsilyl)-
trifluoroacetamide (MSTFA) to volatilize polar components
(Figure 1). This procedure ensures a relatively broad over-
view of the compounds present on the silk. Whilst several
lipids, carbohydrates, amino acids, and acids were present in
both types of silk, two compounds, A and B, proved to be
specific for the extract of active silk. The analysis of the mass
[*] E. Jerhot, Prof. Dr. S. Schulz
Institut fꢀr Organische Chemie,
Technische Universitꢁt Braunschweig
Hagenring 30, 38106 Braunschweig (Germany)
Fax: (+49)531-391-5272
E-mail: stefan.schulz@tu-bs.de
J. A. Stoltz, Prof. Dr. M. C. B. Andrade
Integrative Behaviour and Neuroscience Group,
University of Toronto Scarborough
Toronto, Ontario, M1C 1A4 (Canada)
[**] This work was supported by the Fonds der Chemischen Industrie
and the Natural Sciences and Engineering Research Council of
Canada.
Figure 1. Gas chromatograms of methanol extracts of Latrodectus
hasselti silk after trimethylsilylation with MSTFA. a) Silk of unmated
females; b) silk of mated females.
Supporting information for this article is available on the WWW
Angew. Chem. Int. Ed. 2010, 49, 2037 –2040
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2037