| Abstract |
I. The rodents of Beni Suef Governorate and their seasonal abundance.
1- The abundance of rodent species in crop fields at 7 districts of Beni Suef Gauernorate during 1987 could be arranged in the following descending order
1- The house mouse, Mus mnusculus (77. 24%) .
2- The Nile grass rat, Arvicanthis niloticus (19,94%).
3- The white bellied rat, Rattus rattus frugivorus (2.38%).
4- The Norway rat, Rattus norvegicus (0. 44%) .
- The densities of rodent species in the seven districts of Beni Suef Gouernorate could be arranged into the following sequence :
a) Beba district 178 rodent specimens (73.60% M. musculus 24.72% A. niloticas, and 1.68% R. r. fruqivorus).
b) Somosta district 153 specimens (67.32% Mus musculus 27. 45% A. niloticus, 3. 26% R. r. frugivorus, and 1. 97% R. norvegicus).
c) EL Fashn district 134 specimens (72.39% M. musculus 23. 88% A. niloticus, 2. 24% R. r. fruqivorus, and 1.49% R. norve gicus) .
d) Ehnasia district 130 specimens (80% M. musculus, 18.46 A. niloticus a n d 1 . 9 4% R. r. fruqivorus).
e) Nasser district 118 rodent specimens (85.59% M. musculus, 11.86 A, niloticus, and 2.55% R. r. fruqivorus ).
f ) EL Wasta district 106 specimens (78.30% Al, M. mtasculus 19. 81 A, niloticus, a n d 1. 8 9% R. r. frugivorus).
g) Beni Suef district 97 specimens (83.50% M.musculus 13.40% A, niloticus, and 3.10 R. r. frugivorus).
-The house mouse Mus musculus was the predominant rodent species in all crap fields of the 7 districts of Beni Suef Governorate range between 67.32% to 85.59%; average 77,24%.
2- Five species were found in the four different habitats (village houses, chicken farms, cattle farms, and citrus orchards) at EL Wasta district during the four seasons of 1988:
1-Rattus rattus frugi vorus, Rattus rattus alexandrinus. '
2-Rattus narvegicus 3- Arviccanthis niloticus
4-Acomys cahir.rnus. 5- Alas musculus.
Village houses represented the most preferred habitat followed by chicken farms, citrus orchards and then cattle farms.
- Rattus r. frugi vorus was abundant at houses and chicken farms, with moderate number at citrus orchards, absent at cattle farms.
-Rattus r. alexandeinus was rarely found in houses and chicken farms, it was absent in citrus orchards.
- Rattus norveqicus was abundant at cattle farms and was absent at fruit orchards and houses. Few number were caught in chicken farms.
- Arvannthis nilotscus was found only at citrus orchards and very few numbers were caught from chicken farms surrounded by fields.
- Acomys cahirinus was abundant at village houses and rare at chicken farms near by houses, absent at cattle farms, citrus orchards and fields.
- Mus musculus was found only at citrus orchards and fields.
3- Monthly distribution of rodent species in crop fields at EL wasta district during 1988 and 1989 indicated that the house mouse Mus musculus comprised
93.5% of all specimens trapped, followed by Arvicanthls niloticus 5.5% while Rattus rattus
frugivorus represented 1%.
-The highest indices for Mus musculus, Arvicanthis nilotscus, and Rattus rattus fruqivorus were (0.053), (0.012) and (0.002) during July 1.988/1989, October 1988/1989, and July 1988/1989 respectively.
The average percentage of females during 1988/ 1989 increased throughout the months of autumn season to 53.3, 56.7, and 49% at September, October and November, respectively. The lowest was at June ( av. 31.6%).
-Pregnancy rate of M. musculus was (54%) during June 1988/1989 and the minimum was 8.3% during February 1988/1989. During January 1988,1989 no pregnant. females (0%) were recorded.
- The mean number of embryos/female was 6.5 and the highest number of embryos/female was 10.
- The population density of Mus Musculus Varied from month, to month with a peak in July during 1988 and 1989.
II) Biological studies on house mouse Mus musculus
(1) The female reached its sexual maturity between 48-85 days (av.68.2 days) when weighing 10.5-12.5 gms (av. 11.5 days).
(2) The gestation period ranged from 20-21 days (av. 20.8 days).
(3) The litter size was 3-9 young per litter (av. 5.7)
(4) The incidence of pregnancies per female was 3-6 litters, and period between conception was 10-90 days (av. 45.6 days).
(5) Body weight of the newly born mice after 24 hours from birth, ear flaps, eye opening and weaning was included in the present study.
III) Rodent Damage Assessment:
1- The highest percentage of damage occurred to sweet melons 10.8% (av. 4.82%) and the lowest was to broad beans 0.07% (av. 0.28%).
2- The different crops could be arranged in a desending order according to rodent damage:
sweet melon 4.82%> tomatoes (1.04%) > wheat (0.73%)> maize (0. 48%) >broad beans (0.28%).
IV) Food preference and consumption :
4.1.) Lab trails :- Crushed peanuts was the most preferable food to the house mouse followed by crushed maize,, wheat, sorghum, milled rice, barley, and crushed broad beans was the least. Their ratio relative to wheat were 1.26, 1.16, 1, 0.69, 0.34, 0. 26, and 0. 23 respectively.
4.2) Field trails:- Crushed peanuts was the most preferable bait to the house mouse followed by crushed maize, wheat, sorghum, broad beans, milled rice, while barley seeds were the least as their ratio in relation to wheat was 1.41, 1.12, 1, 0.99, 0.58, 0.50, and 0.44 respectively.
V) Efficacy of bromadiolone , brodifacoum , and diphacinone against Mus musculus.
1- Laboratory evaluation:
Palatability of mice to the free choice feeding anticoagulants used could be arranged according to their acceptance in a descending order as follows . brodifacoum (62.2%) > diphacinone (54.5%) > bromadiolone (46.9%). All of the three rodenticides caused 100% mortality. Average of time to death was shorter in the case of brodifar.oum (0.003%) and bromadiolone (0.005%) (av. 4.6, 5.2 dys.) than diphacinon (0.005%). (av.7.8 dys.).
2) Field performance of bromadialone (0.005%) , brodifacoum (0.003%) and diphacinone (0.005%).
a.) The single dose anticoagulant rodenticides. Weekly pulsing of bromadiolone (0.005%) and brodifacoum (0.003%) wheat grain baits for three consective weeks against Was Mus musculus. Averages of population reduction were similar,68.3% and 71.6%,for , bromadiolone and brodifacoum respectively.
b.) The multi dose anticaagulant rodenticide. Saturation baiting method was used to test diphacinone against Mus musculus. The results showed that diphacinane reduced the mice population by 61.5 and 66.3%.
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