Available online at www.sciencedirect.com
Forensic Science International 177 (2008) e19–e20 www.elsevier.com/locate/forsciint
Rapid communication
Some notes on the nocturnal larviposition by two species of Sarcophaga (Diptera: Sarcophagidae) Devinder Singh, Meenakshi Bharti * Department of Zoology, Punjabi University, Patiala 147002, India Received 28 February 2007; received in revised form 20 June 2007; accepted 27 August 2007 Available online 22 October 2007
Abstract Experiments in the month of September 2005 were performed to study nocturnal larviposition by the flesh flies (Diptera: Sarcophagidae). Two species namely Sarcophaga albiceps Meigen and Sarcophaga hirtipes Wiedemann were observed to deposit their larvae during night time as well. Therefore, possibility of night larviposition by flesh flies should always be taken into consideration while determining age of maggots. # 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Nocturnal larviposition; Flesh flies; Forensic entomology
Immature stages of sarcophagids are often encountered on dead bodies and they may be important forensic indicators to determine the post-mortem interval (PMI). Literature reveals that forensic importance of flesh flies is often undermined, especially if immature stages of blow flies are found on the dead body. Nevertheless, the larvae of sarcophagids showing association with the carrion can play significant forensic role if their age is determined accurately [1]. The issue of nocturnal oviposition/larviposition by calliphorids or sarcophagids remained sceptical until Greenberg [2] and Singh and Bharti [3] reported the phenomena in calliphorids. Pape et al. [4] observed that sarcophagid larvae are strictly diurnal and rarely occur on foliage, tree trunks, etc. until well after sunrise. He further stated that few cases of species of sarcophagids caught at light [5,6] may be due to local disturbance rather than true nocturnal activity. Wooldridge et al. [7] worked on the flight activity of two species of blow flies in dark and, concluded that ‘‘the results presented here do not exclude the possibility that these species can locate an oviposition site and oviposit nocturnally. An especially full moon or artificial lighting might provide strong enough source of illumination, particularly in urban areas. Nevertheless, the probability of
* Corresponding author. E-mail addresses:
[email protected] (D. Singh),
[email protected] (M. Bharti). 0379-0738/$ – see front matter # 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.forsciint.2007.08.007
oriented flight leading to oviposition in the absence of such illumination would appear to be low.’’ Tessmer et al. [8] did not observe nocturnal oviposition on chicken carcasses in urban habitats with lighting, or in rural habitat without lighting. On contrary, in England, under caged conditions, Calliphora vicina laid large quantities of eggs in complete darkness at a temperature of 9.1 8C. The flies did not have access to the bait, but could smell it, and eggs were laid through perforations in the container [9]. The present study reports nocturnal larviposition and flight activity at night by flesh flies. This will eliminate a block of about 10–12 h from calculations from the time of death. 1. Materials and methods The experiment was conducted in an area of the Patiala City, Punjab, India, without any streetlights or other source of illumination. A piece of mutton was put in a Petri dish that was placed on a wooden platform fixed on the top of a pole 6 ft in height and fastened in the ground. A 9 in. band of sticky material (stikem special, by Seabright Laboratories, CA, USA) was applied on the pole, 1 ft above the ground, to prevent the flies from climbing up the pole. The piece of meat was left on this platform from 10 p.m. to 3 a.m. daily for 10 days, i.e. 7–16 September 2005. After exposure, each bait was put in a Ziploc bag along with wood shavings, and its opening sealed. Minute perforations were made in the bag with the help of an entomological pin for air circulation. These bags were brought in the laboratory and placed in empty fly cages at room temperature and observed for the presence of fly maggots. The emerged adults were counted after they died within the respective bags. Identification was carried with the help of keys given by Senior-White et al. [10]. Minimum and maximum temperatures, light
e20
D. Singh, M. Bharti / Forensic Science International 177 (2008) e19–e20
Table 1 Larviposition at night by flesh flies Serial no.
Date
Minimum–maximum temperature (8C)
Relative humidity (%)
Light intensity (lx)
Species
No. of adults reared
1 2
9.9.2005 14.9.2005
24–28 21–26
70 78
0.7 0.8
Sarcophaga albiceps Meigen Sarcophaga hirtipes Wiedemann
20 16
intensity and relative humidity were recorded at the sight of the experiment for the duration of exposure.
2. Results and discussion As has been summarized in Table 1, larviposition by flesh flies occurred twice during the 10-day study period. On the other hand baits put during the day time at the same site (during the experimental duration) almost always attracted flesh flies. The experiment proves that flesh flies can deposit their larvae during night time also with at least two species, i.e. Sarcophaga albiceps Meigen and Sarcophaga hirtipes Wiedamann have a definite tendency for nocturnal larviposition. However, the probability of larviposition and number of larvae during night is comparatively less, pointed out by other workers as well [2,3]. Thus it can be suggested on the basis of this work that the possibility of night larviposition by flesh flies should always be taken into consideration while determining the age of maggots. Moreover, the study has significant bearing at global level, as both the observed species show wide distributional range. S. hirtipes is distributed in India, Egypt, Europe, Palaearctic Asia, Bulgaria, Monaco and Sicily, while S. albiceps occurs in Borneo, China, India, Nepal, Philippines, Ryukyu Islands; Bismarck Archipelago, Europe, Hawaii, Japan, Korea, New Britain, New Guinea, Solomon Islands, Albania, Austria, Belarus, Britain, Bulgaria, Croatia, Czech Republic, Finland, French Mainland, Germany, Hungary, Italian mainland, Latvia, Republic of Moldova, Norwegian mainland, Poland, Romania, Sicily, Slovakia, Spanish mainland including Albora, Sweden including Gotlar, Switzerland, The Netherlands, Ukraine and Yugoslavia including Serbia [11]. We also propose here that there is further scope for undertaking studies to establish the relationship between light intensity and larviposition.
Acknowledgements Financial assistance rendered by CSIR, New Delhi, vide grant No. 9/140(137)/2004-EMRI is greatly acknowledged. We are also thankful to the reviewer of this paper for his intellectual suggestions. References [1] J.H. Byrd, J.L. Castner, Insects of forensic importance, in: J.H. Byrd, J.L. Castner (Eds.), Forensic Entomology—The utility of Arthropods in Legal Investigations, CRC Press, USA, 2001, pp. 43–80. [2] B. Greenberg, Nocturnal larviposition behaviour of blow flies (Diptera: Calliphoridae), J. Med. Entomol. 27 (1990) 807–810. [3] D. Singh, M. Bharti, Further observations on the nocturnal oviposition behaviour of blow flies (Diptera: Calliphoridae), Forensic Sci. Int. 120 (2001) 124–126. [4] T. Pape, D. Dechmann, M.J. Vonhoff, A new species of Sarcofahrtiopsis Hall (Diptera: Sarcophagidae) living in the roosts of Spix’s disk-winged bat Thyroptera tricolor Spix (Chiroptera) in Costa Rica, J. Nat. Hist. 36 (2002) 991–998. [5] W.R. Walton, A new nocturnal species of Tachinidae, Proc. Entomol. Soc. Wash. 17 (1915) 162–164. [6] H.L.F. Audcent, Midnight flies, Entomol. Monthly Mag. 87 (1951) 133. [7] J. Wooldridge, et al., Flight activity of the blow flies, Calliphora vomitoria and Lucilia sericata in the dark, Forensic Sci. Int. 172 (2007) 94–97. [8] J.W. Tessmer, C.L. Meek, V.L. Wright, Circadian patterns of oviposition by necrophilous flies (Diptera: Calliphoridae), Southwest. Entomol. 20 (1995) 439–445. [9] B. Greenberg, J.C. Kunich, Entomology and the Law, Flies as Forensic Indicators, Cambridge University Press, UK, 2002. [10] R. Senior-White, D. Aubertin, J. Smart, The Fauna of British India Including Remainder of the Oriental Region. Diptera. Vol. VI: Family Calliphoridae, Today and Tomorrow’s Printers and Publishers, New Delhi, India, 1940. [11] M.D. Dalfinado, D.E. Hardy, A Catalogue of the Diptera of the Oriental Region. Vol. III: Suborder Cyclorrhapha, The University Press of Hawaii, Honolulu, 1977.
